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Kwok S. The mystery of unidentified infrared emission bands. Astrophys Space Sci 2022; 367:16. [PMID: 35210653 PMCID: PMC8830496 DOI: 10.1007/s10509-022-04045-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 09/16/2021] [Accepted: 01/18/2022] [Indexed: 06/14/2023]
Abstract
A family of unidentified infrared emission (UIE) bands has been observed throughout the Universe. The current observed spectral properties of the UIE bands are summarized. These properties are discussed in the frameworks of different models of the chemical carriers of these bands. The UIE carriers represent a large reservoir of carbon in the Universe, and play a significant role in the physical and chemical processes in the interstellar medium and galactic environment. A correct identification of the carrier of the UIE bands is needed to use these bands as probes of galactic evolution.
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Affiliation(s)
- Sun Kwok
- Department of Earth, Ocean, and Atmospheric Sciences, University of British Columbia, Vancouver, Canada
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2
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Abstract
Herein we present a laboratory rotational study of cyanoacetic acid (CH2(CN)C(O)OH), an organic acid as well as a -CN bearing molecule, that is a candidate molecular system to be detected in the interstellar medium (ISM). Our investigation aims to provide direct experimental frequencies of cyanoacetic acid to guide its eventual astronomical search in low-frequency surveys. Using different jet-cooled rotational spectroscopic techniques in the time domain, we have determined a precise set of the relevant rotational spectroscopic constants, including the 14N nuclear quadrupole coupling constants for the two distinct structures, cis- and gauche- cyanoacetic acid. We believe this work will potentially allow the detection of cyanoacetic acid in the interstellar medium, whose rotational features have remained unknown until now.
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Affiliation(s)
- Miguel Sanz-Novo
- Grupo de Espectroscopía Molecular (GEM), Edificio Quifima, Área de Química-Física, Laboratorios de Espectroscopía y Bioespectroscopía, Parque Científico UVa, Unidad Asociada CSIC, E-47011 Valladolid, Spain
| | - Iker León
- Grupo de Espectroscopía Molecular (GEM), Edificio Quifima, Área de Química-Física, Laboratorios de Espectroscopía y Bioespectroscopía, Parque Científico UVa, Unidad Asociada CSIC, E-47011 Valladolid, Spain
| | - Elena R. Alonso
- Departamento de Química Física, Facultad de Ciencia y Tecnología, Universidad del País Vasco (UPV/EHU), Barrio Sarriena s/n, 48940 Leioa, Spain
- Instituto Biofisika (UPV/EHU, CSIC), University of the Basque Country, Leioa, Spain
| | - Lucie Kolesniková
- Department of Analytical Chemistry, University of Chemistry and Technology, Technická 5, 166 28 Prague 6, Czech Republic
| | - José L. Alonso
- Grupo de Espectroscopía Molecular (GEM), Edificio Quifima, Área de Química-Física, Laboratorios de Espectroscopía y Bioespectroscopía, Parque Científico UVa, Unidad Asociada CSIC, E-47011 Valladolid, Spain
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Cabezas C, Tercero B, Agúndez M, Marcelino N, Pardo JR, de Vicente P, Cernicharo J. Cumulene carbenes in TMC-1: Astronomical discovery of l-H 2C 5 ★. Astron Astrophys 2021; 650:L9. [PMID: 34334798 PMCID: PMC7611420 DOI: 10.1051/0004-6361/202141274] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
We report the first detection in space of the cumulene carbon chain l-H2C5. A total of eleven rotational transitions, with Jup = 7-10 and Ka = 0 and 1, were detected in TMC-1 in the 31.0-50.4 GHz range using the Yebes 40m radio telescope. We derive a column density of (1.8±0.5)×1010 cm-2. In addition, we report observations of other cumulene carbenes detected previously in TMC-1, to compare their abundances with the newly detected cumulene carbene chain. We find that l-H2C5 is ~4.0 times less abundant than the larger cumulene carbene l-H2C6, while it is ~300 and ~500 times less abundant than the shorter chains l-H2C3 and l-H2C4. We discuss the most likely gas-phase chemical routes to these cumulenes in TMC-1 and stress that chemical kinetics studies able to distinguish between different isomers are needed to shed light on the chemistry of C n H2 isomers with n > 3.
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Affiliation(s)
- C. Cabezas
- Grupo de Astrofísica Molecular, Instituto de Física Fundamental (IFF-CSIC), C/ Serrano 121, 28006 Madrid, Spain
| | - B. Tercero
- Observatorio Astronómico Nacional (IGN), C/ Alfonso XII, 3, 28014, Madrid, Spain
- Centro de Desarrollos Tecnológicos, Observatorio de Yebes (IGN), 19141 Yebes, Guadalajara, Spain
| | - M. Agúndez
- Grupo de Astrofísica Molecular, Instituto de Física Fundamental (IFF-CSIC), C/ Serrano 121, 28006 Madrid, Spain
| | - N. Marcelino
- Grupo de Astrofísica Molecular, Instituto de Física Fundamental (IFF-CSIC), C/ Serrano 121, 28006 Madrid, Spain
| | - J. R. Pardo
- Grupo de Astrofísica Molecular, Instituto de Física Fundamental (IFF-CSIC), C/ Serrano 121, 28006 Madrid, Spain
| | - P. de Vicente
- Centro de Desarrollos Tecnológicos, Observatorio de Yebes (IGN), 19141 Yebes, Guadalajara, Spain
| | - J. Cernicharo
- Grupo de Astrofísica Molecular, Instituto de Física Fundamental (IFF-CSIC), C/ Serrano 121, 28006 Madrid, Spain
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Agúndez M, Marcelino N, Tercero B, Cabezas C, de Vicente P, Cernicharo J. O-bearing complex organic molecules at the cyanopolyyne peak of TMC-1: detection of C 2H 3CHO, C 2H 3OH, HCOOCH 3, and CH 3OCH 3. Astron Astrophys 2021; 649:L4. [PMID: 34334796 PMCID: PMC7611417 DOI: 10.1051/0004-6361/202140978] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
We report the detection of the oxygen-bearing complex organic molecules propenal (C2H3CHO), vinyl alcohol (C2H3OH), methyl formate (HCOOCH3), and dimethyl ether (CH3OCH3) toward the cyanopolyyne peak of the starless core TMC-1. These molecules are detected through several emission lines in a deep Q-band line survey of TMC-1 carried out with the Yebes 40m telescope. These observations reveal that the cyanopolyyne peak of TMC-1, which is the prototype of cold dark cloud rich in carbon chains, contains also O-bearing complex organic molecules like HCOOCH3 and CH3OCH3, which have been previously seen in a handful of cold interstellar clouds. In addition, this is the first secure detection of C2H3OH in space and the first time that C2H3CHO and C2H3OH are detected in a cold environment, adding new pieces in the puzzle of complex organic molecules in cold sources. We derive column densities of (2.2 ± 0.3) × 1011 cm™2, (2.5 ± 0.5) × 1012 cm-2, (1.1 ± 0.2) × 1012 cm-2, and (2.5 ± 0.7) × 1012 cm-2 for C2H3CHO, C2H3OH, HCOOCH3, and CH3OCH3, respectively. Interestingly, C2H3OH has an abundance similar to that of its well known isomer acetaldehyde (CH3CHO), with C2H3OH/CH3CHO ~ 1 at the cyanopolyyne peak. We discuss potential formation routes to these molecules and recognize that further experimental, theoretical, and astronomical studies are needed to elucidate the true mechanism of formation of these O-bearing complex organic molecules in cold interstellar sources.
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Affiliation(s)
- M. Agúndez
- Instituto de Física Fundamental, CSIC, Calle Serrano 123, E-28006 Madrid, Spain
| | - N. Marcelino
- Instituto de Física Fundamental, CSIC, Calle Serrano 123, E-28006 Madrid, Spain
| | - B. Tercero
- Observatorio Astronómico Nacional, IGN, Calle Alfonso XII 3, E-28014 Madrid, Spain
- Observatorio de Yebes, IGN, Cerro de la Palera s/n, E-19141 Yebes, Guadalajara, Spain
| | - C. Cabezas
- Instituto de Física Fundamental, CSIC, Calle Serrano 123, E-28006 Madrid, Spain
| | - P. de Vicente
- Observatorio de Yebes, IGN, Cerro de la Palera s/n, E-19141 Yebes, Guadalajara, Spain
| | - J. Cernicharo
- Instituto de Física Fundamental, CSIC, Calle Serrano 123, E-28006 Madrid, Spain
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Agúndez M, Roueff E, Cabezas C, Cernicharo J, Marcelino N. First detection of doubly deuterated methyl acetylene (CHD 2CCH and CH 2DCCD) ★. Astron Astrophys 2021; 649:A171. [PMID: 34334795 PMCID: PMC7611416 DOI: 10.1051/0004-6361/202140843] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
We report the first detection in space of the two doubly deuterated isotopologues of methyl acetylene. The species CHD2CCH and CH2DCCD were identified in the dense core L483 through nine and eight, respectively, rotational lines in the 72-116 GHz range using the IRAM 30m telescope. The astronomical frequencies observed here were combined with laboratory frequencies from the literature measured in the 29-47 GHz range to derive more accurate spectroscopic parameters for the two isotopologues. We derive beam-averaged column densities of (2.7 ± 0.5) × 1012 cm-2 for CHD2CCH and (2.2 ± 0.4) × 1012 cm-2 for CH2DCCD, which translate to abundance ratios CH3CCH/CHD2CCH = 34 ± 10 and CH3CCH/CH2DCCD = 42 ± 13. The doubly deuterated isotopologues of methyl acetylene are only a few times less abundant than the singly deuterated ones, concretely around 2.4 times less abundant than CH3CCD. The abundances of the different deuterated isotopologues with respect to CH3CCH are reasonably accounted for by a gas-phase chemical model in which deuteration occurs from the precursor ions C3H6D+ and C3H5D+, when the ortho-to-para ratio of molecular hydrogen is sufficiently low. This points to gas-phase chemical reactions, rather than grain-surface processes, as responsible for the formation and deuterium fractionation of CH3CCH in L483. The abundance ratios CH2DCCH/CH3CCD = 3.0 ± 0.9 and CHD2CCH/CH2DCCD = 1.25 ± 0.37 observed in L483 are consistent with the statistically expected values of three and one, respectively, with the slight overabundance of CHD2CCH compared to CH2DCCD being well explained by the chemical model.
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Affiliation(s)
- M. Agúndez
- Instituto de Física Fundamental, CSIC, C/ Serrano 123, E-28006 Madrid, Spain
| | - E. Roueff
- LERMA, Observatoire de Paris, PSL Research University, CNRS, Sorbonne Université, F-92190, Meudon, France
| | - C. Cabezas
- Instituto de Física Fundamental, CSIC, C/ Serrano 123, E-28006 Madrid, Spain
| | - J. Cernicharo
- Instituto de Física Fundamental, CSIC, C/ Serrano 123, E-28006 Madrid, Spain
| | - N. Marcelino
- Instituto de Física Fundamental, CSIC, C/ Serrano 123, E-28006 Madrid, Spain
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Rizzo JR, Cernicharo J, Garoía-Miró C. SiO, 29SiO, and 30SiO emission from 67 oxygen-rich stars. A survey of 61 maser lines from 7 to 1 mm. Astrophys J Suppl Ser 2021; 253:44. [PMID: 33854258 PMCID: PMC7610587 DOI: 10.3847/1538-4365/abe469] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Circumstellar environments of oxygen-rich stars are among the strongest SiO maser emitters. Physical processes such as collisions, infrared pumping and overlaps favors the inversion of level population and produce maser emission at different vibrational states. Despite numerous observational and theoretical efforts, we still do not have an unified picture including all the physical processes involved in the SiO maser emission. The aim of this work is to provide homogeneous data in a large sample of oxygen-rich stars. We present a survey of 67 oxygen-rich stars from 7 to 1 mm, in their rotational transitions from J = 1 → 0 to J = 5 → 4, for vibrational numbers v from 0 to 6 in the three main SiO isotopologues. We have used one of the 34 m NASA antennas at Robledo and the IRAM 30 m radio telescope. The first tentative detection of a v = 6 line is reported, as well as the detection of new maser lines. The highest vibrational levels seem confined to small volumes, presumably close to the stars. The J = 1 → 0, v = 2 line flux is greater than the corresponding v = 1 in almost half of the sample, which may confirm a predicted dependence on the pulsation cycle. This database is potentially useful in models which should consider most of the physical agents, time dependency, and mass-loss rates. As by-product, we report detections of 27 thermal rotational lines from other molecules, including isotopologues of SiS, H2S, SO, SO2, and NaCl.
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Affiliation(s)
- J R Rizzo
- Centro de Astrobiología (INTA-CSIC), Ctra. M-108, km. 4, E-28850 Torrejón de Ardoz, Madrid, Spain
- ISDEFE, Beatriz de Bobadilla 3, E-28040 Madrid, Spain
| | - J Cernicharo
- Grupo de Astrofísica Molecular, Instituto de Física Fundamental (IFF-CSIC), C/ Serrano 121, E-28006 Madrid, Spain
| | - C Garoía-Miró
- Joint Institute for VLBI ERIC (JIVE), Oude Hoogeveensedijk 4, 7991 PD Dwingeloo, The Netherlands
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Veselinova A, Agúndez M, Goicoechea JR, Menéndez M, Zanchet A, Verdasco E, Jambrina PG, Aoiz FJ. Quantum study of reaction O( 3 P) + H 2 ( v, j) → OH + H: OH formation in strongly UV-irradiated gas. Astron Astrophys 2021; 648:A76. [PMID: 34257462 PMCID: PMC7611199 DOI: 10.1051/0004-6361/202140428] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
The reaction between atomic oxygen and molecular hydrogen is an important one in astrochemistry as it regulates the abundance of the hydroxyl radical and serves to open the chemistry of oxygen in diverse astronomical environments. However, the existence of a high activation barrier in the reaction with ground state oxygen atoms limits its efficiency in cold gas. In this study we calculate the dependence of the reaction rate coefficient on the rotational and vibrational state of H2 and evaluate the impact on the abundance of OH in interstellar regions strongly irradiated by far-UV photons, where H2 can be efficiently pumped to excited vibrational states. We use a recently calculated potential energy surface and carry out time-independent quantum mechanical scattering calculations to compute rate coefficients for the reaction O(3 P) + H2 (v, j) → OH + H, with H2 in vibrational states v = 0-7 and rotational states j = 0-10. We find that the reaction becomes significantly faster with increasing vibrational quantum number of H2, although even for high vibrational states of H2 (v = 4-5) for which the reaction is barrierless, the rate coefficient does not strictly attain the collision limit and still maintains a positive dependence with temperature. We implemented the calculated state-specific rate coefficients in the Meudon PDR code to model the Orion Bar PDR and evaluate the impact on the abundance of the OH radical. We find the fractional abundance of OH is enhanced by up to one order of magnitude in regions of the cloud corresponding to A V = 1.3-2.3, compared to the use of a thermal rate coefficient for O + H2, although the impact on the column density of OH is modest, of about 60%. The calculated rate coefficients will be useful to model and interpret JWST observations of OH in strongly UV-illuminated environments.
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Affiliation(s)
- A. Veselinova
- Departamento de Química Física, University of Salamanca, Plaza Caidos S/N, E-37008, Salamanca, Spain
- Departamento de Química Física (Unidad Asociada al CSIC), Universidad Complutense de Madrid, Ciudad Universitaria, S/N, E-20840, Madrid, Spain
| | - M. Agúndez
- Instituto de Física Fundamental, CSIC, Calle Serrano 121-123, E-28006, Madrid, Spain
| | - J. R. Goicoechea
- Instituto de Física Fundamental, CSIC, Calle Serrano 121-123, E-28006, Madrid, Spain
| | - M. Menéndez
- Departamento de Química Física (Unidad Asociada al CSIC), Universidad Complutense de Madrid, Ciudad Universitaria, S/N, E-20840, Madrid, Spain
| | - A. Zanchet
- Instituto de Física Fundamental, CSIC, Calle Serrano 121-123, E-28006, Madrid, Spain
| | - E. Verdasco
- Departamento de Química Física (Unidad Asociada al CSIC), Universidad Complutense de Madrid, Ciudad Universitaria, S/N, E-20840, Madrid, Spain
| | - P. G. Jambrina
- Departamento de Química Física, University of Salamanca, Plaza Caidos S/N, E-37008, Salamanca, Spain
| | - F. J. Aoiz
- Departamento de Química Física (Unidad Asociada al CSIC), Universidad Complutense de Madrid, Ciudad Universitaria, S/N, E-20840, Madrid, Spain
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Cernicharo J, Cabezas C, Agúndez M, Tercero B, Pardo JR, Marcelino N, Gallego J, Tercero F, López-Pérez J, de Vicente P. TMC-1, the starless core sulfur factory: Discovery of NCS, HCCS, H 2CCS, H 2CCCS, and C 4S and detection of C 5S. Astron Astrophys 2021; 648:L3. [PMID: 33850333 PMCID: PMC7610586 DOI: 10.1051/0004-6361/202140642] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/10/2023]
Abstract
We report the detection of the sulfur-bearing species NCS, HCCS, H2CCS, H2CCCS, and C4S for the first time in space. These molecules were found towards TMC-1 through the observation of several lines for each species. We also report the detection of C5S for the first time in a cold cloud through the observation of five lines in the 31-50 GHz range. The derived column densities are N(NCS) = (7.8±0.6)×1011 cm-2, N(HCCS) = (6.8±0.6)×1011 cm-2, N(H2CCS) = (7.8±0.8)×1011 cm-2, N(H2CCCS) = (3.7±0.4)×1011 cm-2, N(C4S) = (3.8±0.4)×1010 cm-2, and N(C5S) = (5.0±1.0)×1010 cm-2. The observed abundance ratio between C3S and C4S is 340, that is to say a factor of approximately one hundred larger than the corresponding value for CCS and C3S. The observational results are compared with a state-of-the-art chemical model, which is only partially successful in reproducing the observed abundances. These detections underline the need to improve chemical networks dealing with S-bearing species.
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Affiliation(s)
- J. Cernicharo
- Grupo de Astrofísica Molecular, Instituto de Física Fundamental (IFF-CSIC), C/ Serrano 121, 28006 Madrid, Spain
| | - C. Cabezas
- Grupo de Astrofísica Molecular, Instituto de Física Fundamental (IFF-CSIC), C/ Serrano 121, 28006 Madrid, Spain
| | - M. Agúndez
- Grupo de Astrofísica Molecular, Instituto de Física Fundamental (IFF-CSIC), C/ Serrano 121, 28006 Madrid, Spain
| | - B. Tercero
- Observatorio Astronómico Nacional (IGN), C/ Alfonso XII, 3, 28014, Madrid, Spain
- Centro de Desarrollos Tecnológicos, Observatorio de Yebes (IGN), 19141 Yebes, Guadalajara, Spain
| | - J. R. Pardo
- Grupo de Astrofísica Molecular, Instituto de Física Fundamental (IFF-CSIC), C/ Serrano 121, 28006 Madrid, Spain
| | - N. Marcelino
- Grupo de Astrofísica Molecular, Instituto de Física Fundamental (IFF-CSIC), C/ Serrano 121, 28006 Madrid, Spain
| | - J.D. Gallego
- Centro de Desarrollos Tecnológicos, Observatorio de Yebes (IGN), 19141 Yebes, Guadalajara, Spain
| | - F. Tercero
- Centro de Desarrollos Tecnológicos, Observatorio de Yebes (IGN), 19141 Yebes, Guadalajara, Spain
| | - J.A. López-Pérez
- Centro de Desarrollos Tecnológicos, Observatorio de Yebes (IGN), 19141 Yebes, Guadalajara, Spain
| | - P. de Vicente
- Centro de Desarrollos Tecnológicos, Observatorio de Yebes (IGN), 19141 Yebes, Guadalajara, Spain
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Cernicharo J, Agúndez M, Cabezas C, Marcelino N, Tercero B, Pardo JR, Gallego JD, Tercero F, López-Pérez JA, de Vicente P. Discovery of CH 2CHCCH and detection of HCCN, HC 4N, CH 3CH 2CN, and, tentatively, CH 3CH 2CCH in TMC-1. Astron Astrophys 2021; 647:L2. [PMID: 33833468 PMCID: PMC7610549 DOI: 10.1051/0004-6361/202140434] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
We present the discovery in TMC-1 of vinyl acetylene, CH2CHCCH, and the detection, for the first time in a cold dark cloud, of HCCN, HC4N, and CH3CH2CN. A tentative detection of CH3CH2CCH is also reported. The column density of vinyl acetylene is (1.2±0.2)×1013 cm-2, which makes it one of the most abundant closed-shell hydrocarbons detected in TMC-1. Its abundance is only three times lower than that of propylene, CH3CHCH2. The column densities derived for HCCN and HC4N are (4.4±0.4)×1011 cm-2 and (3.7±0.4)×1011 cm-2, respectively. Hence, the HCCN/HC4N abundance ratio is 1.2±0.3. For ethyl cyanide we derive a column density of (1.1 ±0.3)×1011 cm-2. These results are compared with a state-of-the-art chemical model of TMC-1, which is able to account for the observed abundances of these molecules through gas-phase chemical routes.
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Affiliation(s)
- J Cernicharo
- Grupo de Astrofísica Molecular, Instituto de Física Fundamental (IFF-CSIC), C/ Serrano 121, 28006 Madrid, Spain
| | - M Agúndez
- Grupo de Astrofísica Molecular, Instituto de Física Fundamental (IFF-CSIC), C/ Serrano 121, 28006 Madrid, Spain
| | - C Cabezas
- Grupo de Astrofísica Molecular, Instituto de Física Fundamental (IFF-CSIC), C/ Serrano 121, 28006 Madrid, Spain
| | - N Marcelino
- Grupo de Astrofísica Molecular, Instituto de Física Fundamental (IFF-CSIC), C/ Serrano 121, 28006 Madrid, Spain
| | - B Tercero
- Centro de Desarrollos Tecnológicos, Observatorio de Yebes (IGN), 19141 Yebes, Guadalajara, Spain
- Observatorio Astronómico Nacional (IGN), C/ Alfonso XII, 3, 28014, Madrid, Spain
| | - J R Pardo
- Grupo de Astrofísica Molecular, Instituto de Física Fundamental (IFF-CSIC), C/ Serrano 121, 28006 Madrid, Spain
| | - J D Gallego
- Centro de Desarrollos Tecnológicos, Observatorio de Yebes (IGN), 19141 Yebes, Guadalajara, Spain
| | - F Tercero
- Centro de Desarrollos Tecnológicos, Observatorio de Yebes (IGN), 19141 Yebes, Guadalajara, Spain
| | - J A López-Pérez
- Centro de Desarrollos Tecnológicos, Observatorio de Yebes (IGN), 19141 Yebes, Guadalajara, Spain
| | - P de Vicente
- Centro de Desarrollos Tecnológicos, Observatorio de Yebes (IGN), 19141 Yebes, Guadalajara, Spain
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10
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Cernicharo J, Cabezas C, Agúndez M, Tercero B, Marcelino N, Pardo JR, Tercero F, Gallego J, López-Pérez J, deVicente P. Discovery of allenyl acetylene, H 2CCCHCCH, in TMC-1. A study of the isomers of C 5H 4. Astron Astrophys 2021; 647:L3. [PMID: 33850332 PMCID: PMC7610584 DOI: 10.1051/0004-6361/202140482] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
Abstract
We present the discovery in TMC-1 of allenyl acetylene, H2CCCHCCH, through the observation of nineteen lines with a signal-to-noise ratio ~4-15. For this species, we derived a rotational temperature of 7±1K and a column density of 1.2±0.2×1013 cm-2. The other well known isomer of this molecule, methyl diacetylene (CH3C4H), has also been observed and we derived a similar rotational temperature, Tr=7.0±0.3 K, and a column density for its two states (A and E) of 6.5±0.3×1012 cm-2. Hence, allenyl acetylene and methyl diacetylene have a similar abundance. Remarkably, their abundances are close to that of vinyl acetylene (CH2CHCCH). We also searched for the other isomer of C5H4, HCCCH2CCH (1.4-Pentadiyne), but only a3σ upper limit of 2.5×1012 cm-2 to the column density can be established. These results have been compared to state-of-the-art chemical models for TMC-1, indicating the important role of these hydrocarbons in its chemistry. The rotational parameters of allenyl acetylene have been improved by fitting the existing laboratory data together with the frequencies of the transitions observed in TMC-1.
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Affiliation(s)
- J. Cernicharo
- Grupo de Astrofísica Molecular, Instituto de Física Fundamental (IFF-CSIC), C/ Serrano 121, 28006 Madrid, Spain
| | - C. Cabezas
- Grupo de Astrofísica Molecular, Instituto de Física Fundamental (IFF-CSIC), C/ Serrano 121, 28006 Madrid, Spain
| | - M. Agúndez
- Grupo de Astrofísica Molecular, Instituto de Física Fundamental (IFF-CSIC), C/ Serrano 121, 28006 Madrid, Spain
| | - B. Tercero
- Centro de Desarrollos Tecnológicos, Observatorio de Yebes (IGN), 19141 Yebes, Guadalajara, Spain
- Observatorio Astronómico Nacional (OAN, IGN), Madrid, Spain
| | - N. Marcelino
- Grupo de Astrofísica Molecular, Instituto de Física Fundamental (IFF-CSIC), C/ Serrano 121, 28006 Madrid, Spain
| | - J. R. Pardo
- Grupo de Astrofísica Molecular, Instituto de Física Fundamental (IFF-CSIC), C/ Serrano 121, 28006 Madrid, Spain
| | - F. Tercero
- Centro de Desarrollos Tecnológicos, Observatorio de Yebes (IGN), 19141 Yebes, Guadalajara, Spain
| | - J.D. Gallego
- Centro de Desarrollos Tecnológicos, Observatorio de Yebes (IGN), 19141 Yebes, Guadalajara, Spain
| | - J.A. López-Pérez
- Centro de Desarrollos Tecnológicos, Observatorio de Yebes (IGN), 19141 Yebes, Guadalajara, Spain
| | - P. deVicente
- Centro de Desarrollos Tecnológicos, Observatorio de Yebes (IGN), 19141 Yebes, Guadalajara, Spain
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11
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Agúndez M, Cabezas C, Tercero B, Marcelino N, Gallego JD, de Vicente P, Cernicharo J. Discovery of the propargyl radical (CH 2CCH) in TMC-1: one of the most abundant radicals ever found and a key species for cyclization to benzene in cold dark clouds. Astron Astrophys 2021; 647:L10. [PMID: 33850331 PMCID: PMC7610583 DOI: 10.1051/0004-6361/202140553] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
We present the first identification in interstellar space of the propargyl radical (CH2CCH). This species was observed in the cold dark cloud TMC-1 using the Yebes 40m telescope. The six strongest hyperfine components of the 20,2-10,1 rotational transition, lying at 37.46 GHz, were detected with signal-to-noise ratios in the range 4.6-12.3 σ. We derive a column density of 8.7 × 1013 cm-2 for CH2CCH, which translates to a fractional abundance relative to H2 of 8.7 × 10-9. This radical has a similar abundance to methyl acetylene, with an abundance ratio CH2CCH/CH3CCH close to one. The propargyl radical is thus one of the most abundant radicals detected in TMC-1, and it is probably the most abundant organic radical with a certain chemical complexity ever found in a cold dark cloud. We constructed a gas-phase chemical model and find calculated abundances that agree with, or fall two orders of magnitude below, the observed value depending on the poorly constrained low-temperature reactivity of CH2CCH with neutral atoms. According to the chemical model, the propargyl radical is essentially formed by the C + C2H4 reaction and by the dissociative recombination of C3Hn + ions with n = 4-6. The propargyl radical is believed to control the synthesis of the first aromatic ring in combustion processes, and it probably plays a key role in the synthesis of large organic molecules and cyclization processes to benzene in cold dark clouds.
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Affiliation(s)
- M. Agúndez
- Instituto de Física Fundamental, CSIC, Calle Serrano 123, E-28006 Madrid, Spain
| | - C. Cabezas
- Instituto de Física Fundamental, CSIC, Calle Serrano 123, E-28006 Madrid, Spain
| | - B. Tercero
- Observatorio Astronómico Nacional, IGN, Calle Alfonso XII 3, E-28014 Madrid, Spain
- Observatorio de Yebes, IGN, Cerro de la Palera s/n, E-19141 Yebes, Guadalajara, Spain
| | - N. Marcelino
- Instituto de Física Fundamental, CSIC, Calle Serrano 123, E-28006 Madrid, Spain
| | - J. D. Gallego
- Observatorio de Yebes, IGN, Cerro de la Palera s/n, E-19141 Yebes, Guadalajara, Spain
| | - P. de Vicente
- Observatorio de Yebes, IGN, Cerro de la Palera s/n, E-19141 Yebes, Guadalajara, Spain
| | - J. Cernicharo
- Instituto de Física Fundamental, CSIC, Calle Serrano 123, E-28006 Madrid, Spain
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12
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Cernicharo J, Cabezas C, Bailleux S, Margulès L, Motiyenko R, Zou L, Endo Y, Bermúdez C, Agúndez M, Marcelino N, Lefloch B, Tercero B, de Vicente P. Discovery of the acetyl cation, CH 3CO +, in space and in the laboratory. Astron Astrophys 2021; 646:L7. [PMID: 33828331 PMCID: PMC7610537 DOI: 10.1051/0004-6361/202040076] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
Abstract
Using the Yebes 40m and IRAM 30m radiotelescopes, we detected two series of harmonically related lines in space that can be fitted to a symmetric rotor. The lines have been seen towards the cold dense cores TMC-1, L483, L1527, and L1544. High level of theory ab initio calculations indicate that the best possible candidate is the acetyl cation, CH3CO+, which is the most stable product resulting from the protonation of ketene. We have produced this species in the laboratory and observed its rotational transitions Ju = 10 up to Ju = 27. Hence, we report the discovery of CH3CO+ in space based on our observations, theoretical calculations, and laboratory experiments. The derived rotational and distortion constants allow us to predict the spectrum of CH3CO+ with high accuracy up to 500 GHz. We derive an abundance ratio N(H2CCO)/N(CH3CO+)~44. The high abundance of the protonated form of H2CCO is due to the high proton affinity of the neutral species. The other isomer, H2CCOH+, is found to be 178.9 kJ mol-1 above CH3CO+. The observed intensity ratio between the K=0 and K=1 lines, ~2.2, strongly suggests that the A and E symmetry states have suffered interconversion processes due to collisions with H and/or H2, or during their formation through the reaction of H 3 + with H2CCO.
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Affiliation(s)
- J Cernicharo
- Grupo de Astrofísica Molecular, Instituto de Física Fundamental (IFF-CSIC), C/ Serrano 121, 28006 Madrid, Spain
| | - C Cabezas
- Grupo de Astrofísica Molecular, Instituto de Física Fundamental (IFF-CSIC), C/ Serrano 121, 28006 Madrid, Spain
| | - S Bailleux
- Univ. Lille, CNRS, UMR 8523 - PhLAM - Physique des Lasers Atomes et Molécules, 59000 Lille, France
| | - L Margulès
- Univ. Lille, CNRS, UMR 8523 - PhLAM - Physique des Lasers Atomes et Molécules, 59000 Lille, France
| | - R Motiyenko
- Univ. Lille, CNRS, UMR 8523 - PhLAM - Physique des Lasers Atomes et Molécules, 59000 Lille, France
| | - L Zou
- Univ. Lille, CNRS, UMR 8523 - PhLAM - Physique des Lasers Atomes et Molécules, 59000 Lille, France
| | - Y Endo
- Department of Applied Chemistry, Science Building II, National Chiao Tung University, 1001 Ta-Hsueh Rd., Hsinchu 30010, Taiwan
| | - C Bermúdez
- Grupo de Astrofísica Molecular, Instituto de Física Fundamental (IFF-CSIC), C/ Serrano 121, 28006 Madrid, Spain
| | - M Agúndez
- Grupo de Astrofísica Molecular, Instituto de Física Fundamental (IFF-CSIC), C/ Serrano 121, 28006 Madrid, Spain
| | - N Marcelino
- Grupo de Astrofísica Molecular, Instituto de Física Fundamental (IFF-CSIC), C/ Serrano 121, 28006 Madrid, Spain
| | - B Lefloch
- CNRS, IPAG, Univ. Grenoble Alpes, F-38000 Grenoble, France
| | - B Tercero
- Observatorio Astronómico Nacional (IGN), C/ Alfonso XII, 3, 28014, Madrid, Spain
- Centro de Desarrollos Tecnológicos, Observatorio de Yebes (IGN), 19141 Yebes, Guadalajara, Spain
| | - P de Vicente
- Observatorio Astronómico Nacional (IGN), C/ Alfonso XII, 3, 28014, Madrid, Spain
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13
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Tercero F, López-Pérez JA, Gallego JD, Beltrán F, García O, Patino-Esteban M, López-Fernández I, Gómez-Molina G, Diez M, García-Carreño P, Malo I, Amils R, Serna JM, Albo C, Hernández JM, Vaquero B, González-García J, Barbas L, López-Fernández JA, Bujarrabal V, Gómez-Garrido M, Pardo JR, Santander-García M, Tercero B, Cernicharo J, de Vicente P. Yebes 40 m radio telescope and the broad band NANOCOSMOS receivers at 7 mm and 3 mm for line surveys. Astron Astrophys 2021; 645:A37. [PMID: 33408420 PMCID: PMC7116543 DOI: 10.1051/0004-6361/202038701] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
Abstract
CONTEXT Yebes 40m radio telescope is the main and largest observing instrument at Yebes Observatory and it is devoted to Very Long Baseline Interferometry (VLBI) and single dish observations since 2010. It has been covering frequency bands between 2 GHz and 90 GHz in discontinuous and narrow windows in most of the cases, to match the current needs of the European VLBI Network (EVN) and the Global Millimeter VLBI Array (GMVA). AIMS Nanocosmos project, a European Union funded synergy grant, opened the possibility to increase the instantaneous frequency coverage to observe many molecular transitions with single tunnings in single dish mode. This reduces the observing time and maximises the output from the telescope. METHODS We present the technical specifications of the recently installed 31.5 - 50GHz (Q band) and 72 - 90.5 GHz (W band) receivers along with the main characteristics of the telescope at these frequency ranges. We have observed IRC+10216, CRL 2688 and CRL 618, which harbour a rich molecular chemistry, to demonstrate the capabilities of the new instrumentation for spectral observations in single dish mode. RESULTS The results show the high sensitivity of the telescope in the Q band. The spectrum of IRC+10126 offers a signal to noise ratio never seen before for this source in this band. On the other hand, the spectrum normalised by the continuum flux towards CRL 618 in the W band demonstrates that the 40 m radio telescope produces comparable results to those from the IRAM 30 m radio telescope, although with a smaller sensitivity. The new receivers fulfil one of the main goals of Nanocosmos and open the possibility to study the spectrum of different astrophysical media with unprecedented sensitivity.
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Affiliation(s)
- F. Tercero
- Centro de Desarrollos Tecnológicos, Observatorio de Yebes (IGN), 19141 Yebes, Guadalajara, Spain
| | - J. A. López-Pérez
- Centro de Desarrollos Tecnológicos, Observatorio de Yebes (IGN), 19141 Yebes, Guadalajara, Spain
| | - J. D. Gallego
- Centro de Desarrollos Tecnológicos, Observatorio de Yebes (IGN), 19141 Yebes, Guadalajara, Spain
| | - F. Beltrán
- Centro de Desarrollos Tecnológicos, Observatorio de Yebes (IGN), 19141 Yebes, Guadalajara, Spain
| | - O. García
- Centro de Desarrollos Tecnológicos, Observatorio de Yebes (IGN), 19141 Yebes, Guadalajara, Spain
| | - M. Patino-Esteban
- Centro de Desarrollos Tecnológicos, Observatorio de Yebes (IGN), 19141 Yebes, Guadalajara, Spain
| | - I. López-Fernández
- Centro de Desarrollos Tecnológicos, Observatorio de Yebes (IGN), 19141 Yebes, Guadalajara, Spain
| | - G. Gómez-Molina
- Centro de Desarrollos Tecnológicos, Observatorio de Yebes (IGN), 19141 Yebes, Guadalajara, Spain
| | - M. Diez
- Centro de Desarrollos Tecnológicos, Observatorio de Yebes (IGN), 19141 Yebes, Guadalajara, Spain
| | - P. García-Carreño
- Centro de Desarrollos Tecnológicos, Observatorio de Yebes (IGN), 19141 Yebes, Guadalajara, Spain
| | - I. Malo
- Centro de Desarrollos Tecnológicos, Observatorio de Yebes (IGN), 19141 Yebes, Guadalajara, Spain
| | - R. Amils
- Centro de Desarrollos Tecnológicos, Observatorio de Yebes (IGN), 19141 Yebes, Guadalajara, Spain
| | - J. M. Serna
- Centro de Desarrollos Tecnológicos, Observatorio de Yebes (IGN), 19141 Yebes, Guadalajara, Spain
| | - C. Albo
- Centro de Desarrollos Tecnológicos, Observatorio de Yebes (IGN), 19141 Yebes, Guadalajara, Spain
| | - J. M. Hernández
- Centro de Desarrollos Tecnológicos, Observatorio de Yebes (IGN), 19141 Yebes, Guadalajara, Spain
| | - B. Vaquero
- Centro de Desarrollos Tecnológicos, Observatorio de Yebes (IGN), 19141 Yebes, Guadalajara, Spain
| | - J. González-García
- Centro de Desarrollos Tecnológicos, Observatorio de Yebes (IGN), 19141 Yebes, Guadalajara, Spain
| | - L. Barbas
- Centro de Desarrollos Tecnológicos, Observatorio de Yebes (IGN), 19141 Yebes, Guadalajara, Spain
| | | | - V. Bujarrabal
- Observatorio Astronómico Nacional (IGN), C/ Alfonso XII, 3, 28014, Madrid, Spain
| | - M. Gómez-Garrido
- Centro de Desarrollos Tecnológicos, Observatorio de Yebes (IGN), 19141 Yebes, Guadalajara, Spain
- Observatorio Astronómico Nacional (IGN), C/ Alfonso XII, 3, 28014, Madrid, Spain
| | - J. R. Pardo
- Instituto de Física Fundamental (IFF-CSIC). Group of Molecular Astrophysics, C/ Serrano 123, 28006 Madrid, Spain
| | - M. Santander-García
- Centro de Desarrollos Tecnológicos, Observatorio de Yebes (IGN), 19141 Yebes, Guadalajara, Spain
- Observatorio Astronómico Nacional (IGN), C/ Alfonso XII, 3, 28014, Madrid, Spain
| | - B. Tercero
- Centro de Desarrollos Tecnológicos, Observatorio de Yebes (IGN), 19141 Yebes, Guadalajara, Spain
- Observatorio Astronómico Nacional (IGN), C/ Alfonso XII, 3, 28014, Madrid, Spain
| | - J. Cernicharo
- Instituto de Física Fundamental (IFF-CSIC). Group of Molecular Astrophysics, C/ Serrano 123, 28006 Madrid, Spain
| | - P. de Vicente
- Centro de Desarrollos Tecnológicos, Observatorio de Yebes (IGN), 19141 Yebes, Guadalajara, Spain
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14
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Sanz-Novo M, León I, Alonso JL, Largo A, Barrientos C. Formation of interstellar cyanoacetamide: a rotational and computational study. Astron Astrophys 2020; 644:A3. [PMID: 33594291 PMCID: PMC7116755 DOI: 10.1051/0004-6361/202038766] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/10/2023]
Abstract
CONTEXT Cyanoacetamide is a -CN bearing molecule that is also an amide derivative target molecule in the interstellar medium. AIMS The aim of our investigation is to analyze the feasibility of a plausible formation process of protonated cyanoacetamide under interstellar conditions and to provide direct experimental frequencies of the ground vibrational state of the neutral form in the microwave region in order to enable its eventual identification in the interstellar medium. METHODS We used high-level theoretical computations to study the formation process of protonated cyanoacetamide. Furthermore, we employed a high-resolution laser-ablation molecular beam Fourier transform spectroscopic technique to measure the frequencies of the neutral form. RESULTS We report the first rotational characterization of cyanoacetamide, and a precise set of the relevant rotational spectroscopic constants have been determined as a first step to identifying the molecule in the interstellar medium. We fully explored the potential energy surface to study a gas-phase reaction on the formation process of protonated cyanoacetamide. We found that an exothermic process with no net activation barrier is initiated by the high-energy isomer of protonated hydroxylamine, which leads to protonated cyanoacetamide.
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Affiliation(s)
- M Sanz-Novo
- Grupo de Espectroscopía Molecular (GEM), Edificio Quifima, Área de Química-Física, Laboratorios de Espectroscopía y Bioespectroscopía, Parque Científico UVa, Unidad Asociada CSIC, 47011 Valladolid, Spain
- Computational Chemistry Group, Departamento de Química Física y Química Inorgánica, Facultad de Ciencias, Universidad de Valladolid, 47011 Valladolid, Spain
| | - I León
- Grupo de Espectroscopía Molecular (GEM), Edificio Quifima, Área de Química-Física, Laboratorios de Espectroscopía y Bioespectroscopía, Parque Científico UVa, Unidad Asociada CSIC, 47011 Valladolid, Spain
| | - J L Alonso
- Grupo de Espectroscopía Molecular (GEM), Edificio Quifima, Área de Química-Física, Laboratorios de Espectroscopía y Bioespectroscopía, Parque Científico UVa, Unidad Asociada CSIC, 47011 Valladolid, Spain
| | - A Largo
- Computational Chemistry Group, Departamento de Química Física y Química Inorgánica, Facultad de Ciencias, Universidad de Valladolid, 47011 Valladolid, Spain
| | - C Barrientos
- Computational Chemistry Group, Departamento de Química Física y Química Inorgánica, Facultad de Ciencias, Universidad de Valladolid, 47011 Valladolid, Spain
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15
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Marcelino N, Agúndez M, Tercero B, Cabezas C, Bermúdez C, Gallego JD, de Vicente P, Cernicharo J. Tentative detection of HC 5NH + in TMC-1. Astron Astrophys 2020; 643:L6. [PMID: 33239826 PMCID: PMC7116411 DOI: 10.1051/0004-6361/202039251] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/10/2023]
Abstract
Using the Yebes 40m radio telescope, we report the detection of a series of seven lines harmonically related with a rotational constant B 0=1295.81581 ± 0.00026 MHz and a distortion constant D 0 = 27.3 ± 0.5 Hz towards the cold dense cloud TMC-1. Ab initio calculations indicate that the best possible candidates are the cations HC5NH+ and NC4NH+. From a comparison between calculated and observed rotational constants and other arguments based on proton affinities and dipole moments, we conclude that the best candidate for a carrier of the observed lines is the protonated cyanodiacetylene cation, HC5NH+. The HC5N/HC5NH+ ratio derived in TMC-1 is 240, which is very similar to the HC3N/HC3NH+ ratio. Results are discussed in the framework of a chemical model for protonated molecules in cold dense clouds.
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Affiliation(s)
- N Marcelino
- Grupo de Astrofísica Molecular, Instituto de Física Fundamental (IFF-CSIC), C/Serrano 121, 28006 Madrid, Spain
| | - M Agúndez
- Grupo de Astrofísica Molecular, Instituto de Física Fundamental (IFF-CSIC), C/Serrano 121, 28006 Madrid, Spain
| | - B Tercero
- Centro de Desarrollos Tecnológicos, Observatorio de Yebes (IGN), 19141 Yebes, Guadalajara, Spain
- Observatorio Astronómico Nacional (IGN), C/Alfonso XII, 3, 28014, Madrid, Spain
| | - C Cabezas
- Grupo de Astrofísica Molecular, Instituto de Física Fundamental (IFF-CSIC), C/Serrano 121, 28006 Madrid, Spain
| | - C Bermúdez
- Grupo de Astrofísica Molecular, Instituto de Física Fundamental (IFF-CSIC), C/Serrano 121, 28006 Madrid, Spain
| | - J D Gallego
- Centro de Desarrollos Tecnológicos, Observatorio de Yebes (IGN), 19141 Yebes, Guadalajara, Spain
| | - P de Vicente
- Centro de Desarrollos Tecnológicos, Observatorio de Yebes (IGN), 19141 Yebes, Guadalajara, Spain
| | - J Cernicharo
- Grupo de Astrofísica Molecular, Instituto de Física Fundamental (IFF-CSIC), C/Serrano 121, 28006 Madrid, Spain
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16
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Zeng S, Zhang Q, Jiménez-Serra I, Tercero B, Lu X, Martín-Pintado J, de Vicente P, Rivilla VM, Li S. Cloud-cloud collision as drivers of the chemical complexity in Galactic Centre molecular clouds. Mon Not R Astron Soc 2020; 497:4896-4909. [PMID: 33594294 PMCID: PMC7116751 DOI: 10.1093/mnras/staa2187] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
G+0.693-0.03 is a quiescent molecular cloud located within the Sagittarius B2 (Sgr B2) star-forming complex. Recent spectral surveys have shown that it represents one of the most prolific repositories of complex organic species in the Galaxy. The origin of such chemical complexity, along with the small-scale physical structure and properties of G+0.693-0.03, remains a mystery. In this paper, we report the study of multiple molecules with interferometric observations in combination with single-dish data in G+0.693-0.03. Despite the lack of detection of continuum source, we find small-scale (0.2 pc) structures within this cloud. The analysis of the molecular emission of typical shock tracers such as SiO, HNCO, and CH3OH unveiled two molecular components, peaking at velocities of 57 and 75 km s-1. They are found to be interconnected in both space and velocity. The position-velocity diagrams show features that match with the observational signatures of a cloud-cloud collision. Additionally, we detect three series of class I methanol masers known to appear in shocked gas, supporting the cloud-cloud collision scenario. From the maser emission we provide constraints on the gas kinetic temperatures (∼30-150 K) and H2 densities (104-105 cm-2). These properties are similar to those found for the starburst galaxy NGC253 also using class I methanol masers, suggested to be associated with a cloud-cloud collision. We conclude that shocks driven by the possible cloud-cloud collision is likely the most important mechanism responsible for the high level of chemical complexity observed in G+0.693-0.03.
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Affiliation(s)
- S. Zeng
- School of Physics and Astronomy, Queen Mary University of London, Mile End Road, E1 4NS London, UK
- Center for Astrophysics | Harvard & Smithsonian, 60 Garden Street, Cambridge, MA 02138, USA
- Star and Planet Formation Laboratory, RIKEN Cluster for Pioneering Research, 2-1, Hirosawa, Wako, Saitama 351-0198, Japan
| | - Q. Zhang
- Center for Astrophysics | Harvard & Smithsonian, 60 Garden Street, Cambridge, MA 02138, USA
| | - I. Jiménez-Serra
- Centro de Astrobiología (CSIC-INTA), Carretera de Ajalvir, Km. 4, Torrejón de Ardoz, 28850 Madrid, Spain
| | - B. Tercero
- Observatorio Astroóomico Nacional (OAN-IGN), Calle Alfonso XII, 3, 28014 Madrid, Spain
- Observatorio de Yebes (IGN), Cerro de la Palera S/N, 19141, Guadalajara, Spain
| | - X. Lu
- National Astronomical Observatory of Japan, 2-21-1 Osawa, Mitaka, Tokyo, 181-8588, Japan
| | - J. Martín-Pintado
- Centro de Astrobiología (CSIC-INTA), Carretera de Ajalvir, Km. 4, Torrejón de Ardoz, 28850 Madrid, Spain
| | - P. de Vicente
- Observatorio de Yebes (IGN), Cerro de la Palera S/N, 19141, Guadalajara, Spain
| | - V. M. Rivilla
- INAF-Osservatorio Astrofisico di Arcetri, Largo Enrico Fermi 5, 50125, Florence, Italy
| | - S. Li
- Center for Astrophysics | Harvard & Smithsonian, 60 Garden Street, Cambridge, MA 02138, USA
- Shanghai Astronomical Observatory, Chinese Academy of Sciences, 80 Nandan Road, Shanghai 200030, China
- University of Chinese Academy of Sciences, 19A Yuquanlu, Beijing 100049, China
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17
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Cernicharo J, Marcelino N, Agúndez M, Bermúdez C, Cabezas C, Tercero B, Pardo JR. Discovery of HC 4NC in TMC-1: A study of the isomers of HC 3N, HC 5N, and HC 7N. Astron Astrophys 2020; 642:L8. [PMID: 33239824 PMCID: PMC7116413 DOI: 10.1051/0004-6361/202039274] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
Abstract
We present a study of the isocyano isomers of the cyanopolyynes HC3N, HC5N, and HC7N in TMC-1 and IRC+10216 carried out with the Yebes 40m radio telescope. This study has enabled us to report the detection, for the first time in space, of HCCCCNC in TMC-1 and to give upper limits for HC6NC in the same source. In addition, the deuterated isotopologues of HCCNC and HNCCC were detected, along with all 13C substitutions of HCCNC, also for the first time in space. The abundance ratios of HC3N and HC5N, with their isomers, are very different in TMC-1 and IRC+10216, namely, N(HC5N)/N(HC4NC) is ~300 and ≥2100, respectively. We discuss the chemistry of the metastable isomers of cyanopolyynes in terms of the most likely formation pathways and by comparing observational abundance ratios between different sources.
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Affiliation(s)
- J. Cernicharo
- Grupo de Astrofísica Molecular, Instituto de Física Fundamental (IFF-CSIC), C/ Serrano 121, 28006 Madrid, Spain
| | - N. Marcelino
- Grupo de Astrofísica Molecular, Instituto de Física Fundamental (IFF-CSIC), C/ Serrano 121, 28006 Madrid, Spain
| | - M. Agúndez
- Grupo de Astrofísica Molecular, Instituto de Física Fundamental (IFF-CSIC), C/ Serrano 121, 28006 Madrid, Spain
| | - C. Bermúdez
- Grupo de Astrofísica Molecular, Instituto de Física Fundamental (IFF-CSIC), C/ Serrano 121, 28006 Madrid, Spain
| | - C. Cabezas
- Grupo de Astrofísica Molecular, Instituto de Física Fundamental (IFF-CSIC), C/ Serrano 121, 28006 Madrid, Spain
| | - B. Tercero
- Centro de Desarrollos Tecnológicos, Observatorio de Yebes (IGN), 19141 Yebes, Guadalajara, Spain
- Observatorio Astronómico Nacional (OAN, IGN), Madrid, Spain
| | - J. R. Pardo
- Grupo de Astrofísica Molecular, Instituto de Física Fundamental (IFF-CSIC), C/ Serrano 121, 28006 Madrid, Spain
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18
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Cernicharo J, Marcelino N, Agúndez M, Endo Y, Cabezas C, Bermúdez C, Tercero B, de Vicente P. Discovery of HC 3O + in space: The chemistry of O-bearing species in TMC-1. Astron Astrophys 2020; 642:L17. [PMID: 33239825 PMCID: PMC7116414 DOI: 10.1051/0004-6361/202039351] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
Abstract
Using the Yebes 40m and IRAM 30m radio telescopes, we detected a series of harmonically related lines with a rotational constant B 0=4460.590±0.001 MHz and a distortion constant D 0=0.511 ±0.005 kHz towards the cold dense core TMC-1. High-level-of-theory ab initio calculations indicate that the best possible candidate is protonated tricarbon monoxide, HC3O+. We have succeeded in producing this species in the laboratory and observed its J u -J l = 2-1 and 3-2 rotational transitions. Hence, we report the discovery of HC3O+ in space based on our observations, theoretical calculations, and laboratory experiments. We derive an abundance ratio N(C3O)/N(HC3O+)~7. The high abundance of the protonated form of C3O is due to the high proton affinity of the neutral species. The chemistry of O-bearing species is modelled, and predictions are compared to the derived abundances from our data for the most prominent O-bearing species in TMC-1.
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Affiliation(s)
- J Cernicharo
- Grupo de Astrofísica Molecular, Instituto de Física Fundamental (IFF-CSIC), C/ Serrano 121, 28006 Madrid, Spain
| | - N Marcelino
- Grupo de Astrofísica Molecular, Instituto de Física Fundamental (IFF-CSIC), C/ Serrano 121, 28006 Madrid, Spain
| | - M Agúndez
- Grupo de Astrofísica Molecular, Instituto de Física Fundamental (IFF-CSIC), C/ Serrano 121, 28006 Madrid, Spain
| | - Y Endo
- Department of Applied Chemistry, Science Building II, National Chiao Tung University, 1001 Ta-Hsueh Rd., Hsinchu 30010, Taiwan
| | - C Cabezas
- Grupo de Astrofísica Molecular, Instituto de Física Fundamental (IFF-CSIC), C/ Serrano 121, 28006 Madrid, Spain
| | - C Bermúdez
- Grupo de Astrofísica Molecular, Instituto de Física Fundamental (IFF-CSIC), C/ Serrano 121, 28006 Madrid, Spain
| | - B Tercero
- Observatorio Astronómico Nacional (IGN), C/ Alfonso XII, 3, 28014, Madrid, Spain
- Centro de Desarrollos Tecnológicos, Observatorio de Yebes (IGN), 19141 Yebes, Guadalajara, Spain
| | - P de Vicente
- Centro de Desarrollos Tecnológicos, Observatorio de Yebes (IGN), 19141 Yebes, Guadalajara, Spain
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Cernicharo J, Marcelino N, Pardo JR, Agúndez M, Tercero B, de Vicente P, Cabezas C, Bermúdez C. Interstellar nitrile anions: Detection of C 3N - and C 5N - in TMC-1 . Astron Astrophys 2020; 641:L9. [PMID: 33173234 PMCID: PMC7116340 DOI: 10.1051/0004-6361/202039231] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
Abstract
We report on the first detection of C3N- and C5N- towards the cold dark core TMC-1 in the Taurus region, using the Yebes 40 m telescope. The observed C3N/C3N- and C5N/C5N- abundance ratios are ~140 and ~2, respectively; that is similar to those found in the circumstellar envelope of the carbon-rich star IRC +10216. Although the formation mechanisms for the neutrals are different in interstellar (ion-neutral reactions) and circumstellar clouds (photodissociation and radical-neutral reactions), the similarity of the C3N/C3N- and C5N/C5N- abundance ratios strongly suggests a common chemical path for the formation of these anions in interstellar and circumstellar clouds. We discuss the role of radiative electronic attachment, reactions between N atoms and carbon chain anions C n -, and that of H- reactions with HC3N and HC5N as possible routes to form C n N-. The detection of C5N- in TMC-1 gives strong support for assigning to this anion the lines found in IRC +10216, as it excludes the possibility of a metal-bearing species, or a vibrationally excited state. New sets of rotational parameters have been derived from the observed frequencies in TMC-1 and IRC +10216 for C5N- and the neutral radical C5N.
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Affiliation(s)
- J Cernicharo
- Grupo de Astrofísica Molecular, Instituto de Física Fundamental (IFF-CSIC), C/ Serrano 121, 28006 Madrid, Spain
| | - N Marcelino
- Grupo de Astrofísica Molecular, Instituto de Física Fundamental (IFF-CSIC), C/ Serrano 121, 28006 Madrid, Spain
| | - J R Pardo
- Grupo de Astrofísica Molecular, Instituto de Física Fundamental (IFF-CSIC), C/ Serrano 121, 28006 Madrid, Spain
| | - M Agúndez
- Grupo de Astrofísica Molecular, Instituto de Física Fundamental (IFF-CSIC), C/ Serrano 121, 28006 Madrid, Spain
| | - B Tercero
- Centro de Desarrollos Tecnológicos, Observatorio de Yebes (IGN), 19141 Yebes, Guadalajara, Spain
- Observatorio Astronómico Nacional (IGN), C/ Alfonso XII, 3, 28014, Madrid, Spain
| | - P de Vicente
- Centro de Desarrollos Tecnológicos, Observatorio de Yebes (IGN), 19141 Yebes, Guadalajara, Spain
| | - C Cabezas
- Grupo de Astrofísica Molecular, Instituto de Física Fundamental (IFF-CSIC), C/ Serrano 121, 28006 Madrid, Spain
| | - C Bermúdez
- Grupo de Astrofísica Molecular, Instituto de Física Fundamental (IFF-CSIC), C/ Serrano 121, 28006 Madrid, Spain
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Cabezas C, Bermúdez C, Tercero B, Cernicharo J. The millimeter-wave spectrum and astronomical search for ethyl methyl sulfide. Astron Astrophys 2020; 639:A129. [PMID: 32724240 PMCID: PMC7115819 DOI: 10.1051/0004-6361/202038177] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
CONTEXT Sulfur-containing molecules constitute only 8% of the molecules observed in the interstellar medium (ISM), in spite of the fact that sulfur has been shown to be an abundant element in the ISM. In order to understand the chemical behavior of the ISM and specific cases like the missing sulfur reservoir, a detailed chemical molecular composition in the ISM must be mapped out. AIMS Our goal is to investigate the rotational spectrum of ethyl methyl sulfide, CH3CH2SCH3, which ms to be a potential candidate for observation in the ISM since the simpler analogs, CH3SH and CH3CH2SH, have already been detected. Rotational spectrum of ethyl methyl sulfide has been observed before, but its experimental rotational parameters are not precise enough to allow its detection in the ISM. METHODS The rotational spectrum of ethyl methyl sulfide in the frequency range 72-116.5 GHz was measured using a broadband millimeter-wave spectrometer based on radio astronomy receivers with fast Fourier transform backends. The spectral searches and identification of the vibrational excited states of ethyl methyl sulfide was supported by high-level ab initio calculations on the harmonic and anharmonic force fields. RESULTS The rotational spectra for the trans and gauche conformers of ethyl methyl sulfide was analyzed, and a total of 172 and 259 rotational transitions were observed for each one, respectively. The observation of A - E internal rotation splittings allowed the experimental determination of the V 3 hindered internal rotation barrier height for both trans and gauche species. In addition, the vibrational excited states, resulting from the lowest frequency vibrational mode ν 30 were identified for both conformers. The new experimental rotational parameters were employed to search for ethyl methyl sulfide in the warm and cold molecular clouds Orion KL, Sgr B2(N), B1-b and TMC-1, using the spectral surveys captured by IRAM 30 m at 3 mm and 2 mm.
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Affiliation(s)
- C. Cabezas
- Instituto de Física Fundamental (IFF-CSIC). Group of Molecular Astrophysics, C/Serrano 123, 28006 Madrid, Spain
| | - C. Bermúdez
- Instituto de Física Fundamental (IFF-CSIC). Group of Molecular Astrophysics, C/Serrano 123, 28006 Madrid, Spain
| | - B. Tercero
- Observatorio de Yebes (IGN), Cerro de la Palera s/n, 19141 Yebes, Guadalajara, Spain
- Observatorio Astronómico Nacional (OAN-IGN), C/Alfonso XII 3, 28014 Madrid, Spain
| | - J. Cernicharo
- Instituto de Física Fundamental (IFF-CSIC). Group of Molecular Astrophysics, C/Serrano 123, 28006 Madrid, Spain
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Etim EE, Gorai P, Ghosh R, Das A. Detectable interstellar anions: Examining the key factors. Spectrochim Acta A Mol Biomol Spectrosc 2020; 230:118011. [PMID: 31981854 DOI: 10.1016/j.saa.2019.118011] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/11/2019] [Revised: 12/23/2019] [Accepted: 12/27/2019] [Indexed: 06/10/2023]
Abstract
Electron attachment energy (eAE) and the dipole moment of the neutral molecules are related to the radiative electron attachment (REA) process, which is an important formation route of interstellar anions under various astrophysical environments. Electron attachment energies (eAEs) have been calculated for over 80 carbon chain neutral molecules; Cn, CnX (X = N, O, S, H, Si, P), HCnN using ab initio quantum chemical method. Dipole moments of these neutral species and those of their corresponding anions are also theoretically estimated. The anions are found to be significantly more stable than their corresponding neutral analogues in most of the carbon chains considered. The high eAEs and the large dipole moment of most of the neutral species suggest a high detectability of their corresponding anions in the interstellar medium if they are abundant. Members of the C2nO-, C2nS-, C2n1Si, HC2nN-, CnP-, and C2n chains with increasing n are good candidates for future astronomical detection including the higher members of the C2nH- and C2n-1N- groups whose lower members have been observed.
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Affiliation(s)
- Emmanuel E Etim
- Department of Chemical Sciences, Federal University Wukari, Katsina-Ala Road, P.M.B. 1020 Wukari, Taraba State, Nigeria.
| | - Prasanta Gorai
- Indian Centre for Space Physics, 43 Chalantika, Garia Station Road, Kolkata 700 084, India
| | - Rana Ghosh
- Indian Centre for Space Physics, 43 Chalantika, Garia Station Road, Kolkata 700 084, India
| | - Ankan Das
- Indian Centre for Space Physics, 43 Chalantika, Garia Station Road, Kolkata 700 084, India
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Hudson RL, Loeffler MJ, Ferrante RF, Gerakines PA, Coleman FM. Testing Densities and Refractive Indices of Extraterrestrial Ice Components Using Molecular Structures - Organic Compounds and Molar Refractions. Astrophys J 2020; 891:22. [PMID: 35237007 PMCID: PMC8886572 DOI: 10.3847/1538-4357/ab6efa] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
The use of infrared spectra to determine molecular abundances of icy astronomical objects and to study their chemistry requires laboratory measurements of reference spectra and related quantities, such as the index of refraction (n) and density (ρ) of candidate ices. Here we present new n and ρ measurements on ices involving over thirty C-, H-, and O-containing compounds, both acyclic and cyclic, representing seven chemical families. We examine the results in a way that is rare in the astrochemical literature, namely one in which data from an ice formed from molecules of a particular chemical family are compared to measurements on another member of the same family, such as of a homologous series or a pair of isomers. Apart from the intrinsic usefulness of the n and ρ data, a structure-based comparison can help establish trends and identify possibly spurious results. As liquid-phase data sometimes are used in low-temperature astrochemical work in the absence of solid-phase measurements, we compare our new ice results to those for the corresponding room-temperature liquids. We emphasize the use of our n and ρ data to compute the molar refraction (R M ) for each of our ices, and how the resulting R M values compare to those expected from molecular structures. The use of calculated RM values and measured n values to calculate ice densities, in the absence of direct measurements, also is addressed.
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Affiliation(s)
- Reggie L. Hudson
- Astrochemistry Laboratory, NASA Goddard Space Flight Center, Greenbelt, MD, 20771 USA
| | - Mark J. Loeffler
- Astrochemistry Laboratory, NASA Goddard Space Flight Center, Greenbelt, MD, 20771 USA
- Department of Physics and Astronomy, Northern Arizona University, Flagstaff, AZ 86011 USA
| | | | - Perry A. Gerakines
- Astrochemistry Laboratory, NASA Goddard Space Flight Center, Greenbelt, MD, 20771 USA
| | - Falvia M. Coleman
- Astrochemistry Laboratory, NASA Goddard Space Flight Center, Greenbelt, MD, 20771 USA
- InuTeq, LLC, Beltsville, MD 20705 USA
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Hudson RL, Ferrante RF. Quantifying acetaldehyde in astronomical ices and laboratory analogues: IR spectra, intensities, 13C shifts, and radiation chemistry. Mon Not R Astron Soc 2020; 492:283-293. [PMID: 35237025 PMCID: PMC8886571 DOI: 10.1093/mnras/stz3323] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Acetaldehyde is of interest to astrochemists for its relevance to both interstellar and cometary chemistry, but little infrared (IR) spectral data have been published for the solid phases of this compound. Here we present IR spectra of three forms of solid acetaldehyde, with spectra for one form being published for the first time. Direct measurements of band strengths and absorption coefficients also are reported for the first time for amorphous aldehyde, the form of greatest interest for astrochemical work. An acetaldehyde band strength at ~1350 cm-1 that has been used as a reference for about 20 years is seen to be in error by about 80% when compared to the direct measurements presented here. Spectra and peak positions also are presented for H13C(O)13CH3, and then used for the first identification of ketene as a radiation product of solid acetaldehyde.
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Affiliation(s)
- Reggie L Hudson
- Astrochemistry Laboratory, NASA Goddard Space Flight Center, Greenbelt, MD 20771 USA
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24
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Li Q, Li A, Jiang BW. How much graphene in space? Mon Not R Astron Soc 2019; 490:3875-3881. [PMID: 31762496 PMCID: PMC6859651 DOI: 10.1093/mnras/stz2740] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/12/2019] [Revised: 09/10/2019] [Accepted: 09/24/2019] [Indexed: 06/10/2023]
Abstract
The possible presence of graphene in the interstellar medium (ISM) is examined by comparing the interstellar extinction curve with the ultraviolet absorption of graphene calculated from its dielectric functions experimentally obtained with the electron energy loss spectroscopy (EELS) method. Based on the absence in the interstellar extinction curve of the [Formula: see text] π-π* electronic interband transition of graphene, we place an upper limit of [Formula: see text] of C/H on the interstellar graphene abundance, exceeding the previous estimate by a factor of [Formula: see text]3 which made use of the dielectric functions measured with the spectroscopic ellipsometry (SE) method. Compared with the SE method which measures graphene in air (and hence its surface is contaminated) in a limited energy range of [Formula: see text]0.7-5 [Formula: see text], the EELS probes a much wider energy range of [Formula: see text]0-50 [Formula: see text] and is free of contamination. The fact that the EELS dielectric functions are substantially smaller than that of SE naturally explains why a higher upper limit on the graphene abundance is derived with EELS. Inspired by the possible detection of C24, a planar graphene sheet, in several Galactic and extragalactic planetary nebulae, we also examine the possible presence of C24 in the diffuse ISM by comparing the model IR emission of C24 with the observed IR emission of the Galactic cirrus and the diffuse ISM towards l = 44°20' and b = -0°20'. An upper limit of [Formula: see text] on C24 is also derived from the absence of the characteristic vibrational bands of C24 at [Formula: see text]6.6, 9.8, and 20 [Formula: see text] in the observed IR emission.
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Affiliation(s)
- Qi Li
- Department of Astronomy, Beijing Normal University, Beijing 100875, China
- Department of Physics and Astronomy, University of Missouri, Columbia, MO 65211, USA
| | - Aigen Li
- Department of Physics and Astronomy, University of Missouri, Columbia, MO 65211, USA
| | - B W Jiang
- Department of Astronomy, Beijing Normal University, Beijing 100875, China
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Abstract
CONTEXT The James Webb Space Telescope (JWST) will deliver an unprecedented quantity of high-quality spectral data over the 0.6-28 μm range. It will combine sensitivity, spectral resolution, and spatial resolution. Specific tools are required to provide efficient scientific analysis of such large data sets. AIMS Our aim is to illustrate the potential of unsupervised learning methods to get insights into chemical variations in the populations that carry the aromatic infrared bands (AIBs), more specifically polycyclic aromatic hydrocarbon (PAH) species and carbonaceous very small grains (VSGs). METHODS We present a method based on linear fitting and blind signal separation for extracting representative spectra for a spectral data set. The method is fast and robust, which ensures its applicability to JWST spectral cubes. We tested this method on a sample of ISO-SWS data, which resemble most closely the JWST spectra in terms of spectral resolution and coverage. RESULTS Four representative spectra were extracted. Their main characteristics appear consistent with previous studies with populations dominated by cationic PAHs, neutral PAHs, evaporating VSGs, and large ionized PAHs, known as the PAH x population. In addition, the 3 μm range, which is considered here for the first time in a blind signal separation (BSS) method, reveals the presence of aliphatics connected to neutral PAHs. Each representative spectrum is found to carry second-order spectral signatures (e.g., small bands), which are connected with the underlying chemical diversity of populations. However, the precise attribution of theses signatures remains limited by the combined small size and heterogeneity of the sample of astronomical spectra available in this study. CONCLUSIONS The upcoming JWST data will allow us to overcome this limitation. The large data sets of hyperspectral images provided by JWST analysed with the proposed method, which is fast and robust, will open promising perspectives for our understanding of the chemical evolution of the AIB carriers.
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Affiliation(s)
- S Foschino
- Institut de Recherche en Astrophysique et Planetologie, Université de Toulouse, CNRS, CNES, UPS, Toulouse, France, 9 Av. du colonel Roche, 31028 Toulouse Cedex 04, France
| | - O Berné
- Institut de Recherche en Astrophysique et Planetologie, Université de Toulouse, CNRS, CNES, UPS, Toulouse, France, 9 Av. du colonel Roche, 31028 Toulouse Cedex 04, France
| | - C Joblin
- Institut de Recherche en Astrophysique et Planetologie, Université de Toulouse, CNRS, CNES, UPS, Toulouse, France, 9 Av. du colonel Roche, 31028 Toulouse Cedex 04, France
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Sharma MK. Vinyl cyanide (CH 2CHCN) in interstellar space: potential spectral lines for its detection. Heliyon 2019; 5:e02384. [PMID: 31508529 PMCID: PMC6726722 DOI: 10.1016/j.heliyon.2019.e02384] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2019] [Revised: 06/21/2019] [Accepted: 08/23/2019] [Indexed: 11/29/2022] Open
Abstract
Vinyl cyanide is a molecule having planar geometry with electric dipole moment components, μa=3.821D and μb=0.687D. Thus, a-type transitions are very strong as compared to b-type transitions, and are considered in this investigation. The rotational levels for a-type transitions, may be divided into two distinct groups: one group having odd values of ka and the other having even values of ka. Using the known values of rotational and centrifugal distortion constant along with the electric dipole moment μa, we have calculated energies of lower 120 rotational levels, having energy up to 92cm−1, for each group, and the probabilities for radiative transitions between the levels. These radiative transition probabilities in conjunction with the scaled values of collisional rate coefficients are used in the Sobolev Large Velocity Gradient analysis. Out of a large number of lines, we have selected the strongest ones. In the low lying levels, besides the 4 observed lines of CH2CHCN, we have discussed about 8 additional transitions, of which 2 showing the phenomenon of anomalous absorption and 6 showing emission feature are found. These lines may play important role for the search of vinyl cyanide in a cosmic object.
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Affiliation(s)
- Mohit K Sharma
- Amity Centre for Astronomy & Astrophysics, Amity Institute of Applied Sciences, Amity University, Sector 125, Noida 201313, U.P., India
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27
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Cabezas C, Bermúdez C, Gallego JD, Tercero B, Hernández JM, Tanarro I, Herrero VJ, Doménech JL, Cernicharo J. The millimeter-wave spectrum and astronomical search of succinonitrile and its vibrational excited states ★. Astron Astrophys 2019; 629:A35. [PMID: 31485081 PMCID: PMC6726483 DOI: 10.1051/0004-6361/201935899] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
CONTEXT Dinitriles with a saturated hydrocarbon skeleton and a -C≡N group at each end can have large electric dipole moments. Their formation can be related to highly reactive radicals such as CH2CN, C2N or CN. Thus, these saturated dinitriles are potential candidates to be observed in the ISM. AIMS Our goal is the investigation of the rotational spectrum of one of the simplest dinitriles N≡C-CH2-CH2-C≡N, succinonitrile, whose actual rotational parameters are not precise enough to allow its detection in the ISM. In addition, the rotational spectra for its vibrational exicted states will be analyzed. METHODS The rotational spectra of succinonitrile was measured in the frequency range 72-116.5 GHz using a new broadband millimeter-wave spectrometer based on radio astronomy receivers with Fast Fourier Transform backends. The identification of the vibrational excited states of succinonitrile was supported by high-level ab initio calculations on the harmonic and anharmonic force fields. RESULTS A total of 459 rotational transitions with maximum values of J and Ka quantum numbers 70 and 14, respectively, were measured for the ground vibrational state of succinonitrile. The analysis allowed us to accurately determine the rotational, quartic and sextic centrifugal distortion constants. Up to eleven vibrational excited states, resulting from the four lowest frequency vibrational modes ν 13, ν 12, ν 24 and ν 23 were identified. In addition to the four fundamental modes, we observed overtones together with some combination states. The rotational parameters for the ground state were employed to unsuccessfully search for succinonitrile in the cold and warm molecular clouds Orion KL, Sgr B2(N), B1-b and TMC-1, using the spectral surveys captured by IRAM 30m at 3mm and the Yebes 40m at 1.3cm and 7mm. CONCLUSIONS
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Affiliation(s)
- C. Cabezas
- Instituto de Física Fundamental (IFF-CSIC). Group of Molecular Astrophysics, C/ Serrano 123, 28006 Madrid, Spain
| | - C. Bermúdez
- Instituto de Física Fundamental (IFF-CSIC). Group of Molecular Astrophysics, C/ Serrano 123, 28006 Madrid, Spain
| | - J. D. Gallego
- Centro de Desarrollos Tecnológicos, Observatorio de Yebes (IGN), 19141 Yebes, Guadalajara, Spain
| | - B. Tercero
- Centro de Desarrollos Tecnológicos, Observatorio de Yebes (IGN), 19141 Yebes, Guadalajara, Spain
- Observatorio Astronómico Nacional (OAN-IGN), C/ Alfonso XII 3, 28014 Madrid, Spain
| | - J. M. Hernández
- Centro de Desarrollos Tecnológicos, Observatorio de Yebes (IGN), 19141 Yebes, Guadalajara, Spain
| | - I. Tanarro
- Instituto de Estructura de la Materia (IEM-CSIC). Molecular Physics Department. C/Serrano 123, 28006 Madrid, Spain
| | - V. J. Herrero
- Instituto de Estructura de la Materia (IEM-CSIC). Molecular Physics Department. C/Serrano 123, 28006 Madrid, Spain
| | - J. L. Doménech
- Instituto de Estructura de la Materia (IEM-CSIC). Molecular Physics Department. C/Serrano 123, 28006 Madrid, Spain
| | - J. Cernicharo
- Instituto de Física Fundamental (IFF-CSIC). Group of Molecular Astrophysics, C/ Serrano 123, 28006 Madrid, Spain
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Scirè C, Urso RG, Fulvio D, Baratta GA, Palumbo ME. Mid-IR band strength, density, refractive index, and thermal evolution study for solid CH 2DOH pure and in astrophysical relevant mixtures. Spectrochim Acta A Mol Biomol Spectrosc 2019; 219:288-296. [PMID: 31051423 DOI: 10.1016/j.saa.2019.04.021] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/29/2019] [Revised: 04/12/2019] [Accepted: 04/12/2019] [Indexed: 06/09/2023]
Abstract
We present a novel experimental study on solid CH2DOH pure and in astrophysical relevant mixtures. Solid samples were accreted under ultra high vacuum conditions at 17 K and were analyzed by mid-infrared transmission spectroscopy. Refractive index, density, and mid-IR band strength values were measured for pure solid CH2DOH. The refractive index was also measured for CH2DOH:H2O, CH2DOH:CO, and CH2DOH:CH3OH mixtures. For all samples, the thermal evolution of the main band profile was studied. We used the interference laser technique (HeNe laser, λ = 543.5 nm) to measure the samples thickness and a numerical method to measure the refractive index starting from the amplitude of the interference curve. We obtained the ice density through the Lorentz-Lorenz relation. To calculate the band strength values we used the linear fit of the integrated band intensities with respect to the column densities. Samples deposited at 17 K were warmed up to their sublimation temperature. Spectra were taken at selected temperatures to study their thermal evolution. The results are discussed in view of their relevance for the interpretation of astronomical IR spectra.
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Affiliation(s)
- C Scirè
- INAF - Osservatorio Astrofisico di Catania, via Santa Sofia 78, I-95123 Catania, Italy.
| | - R G Urso
- INAF - Osservatorio Astrofisico di Catania, via Santa Sofia 78, I-95123 Catania, Italy; Institut d'Astrophysique Spatiale, CNRS/Université Paris-Sud, Université Paris-Saclay, batiment 121, Université Paris-Sud, 91405 Orsay Cedex, France
| | - D Fulvio
- Departamento de Fsica, Pontifcia Universidade Catolica do Rio de Janeiro, Rua Marqus de So Vicente 225, 22451-900, Rio de Janeiro, RJ, Brazil
| | - G A Baratta
- INAF - Osservatorio Astrofisico di Catania, via Santa Sofia 78, I-95123 Catania, Italy
| | - M E Palumbo
- INAF - Osservatorio Astrofisico di Catania, via Santa Sofia 78, I-95123 Catania, Italy
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Rivière-Marichalar P, Fuente A, Goicoechea JR, Pety J, Le Gal R, Gratier P, Guzmán V, Roueff E, Loison JC, Wakelam V, Gerin M. Abundances of sulphur molecules in the Horsehead nebula First NS + detection in a photodissociation region. Astron Astrophys 2019; 628:A16. [PMID: 31511745 PMCID: PMC6739222 DOI: 10.1051/0004-6361/201935354] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
CONTEXT Sulphur is one of the most abundant elements in the Universe (S/H∼1.3×10 -5 ) and plays a crucial role in biological systems on Earth. The understanding of its chemistry is therefore of major importance. AIMS Our goal is to complete the inventory of S-bearing molecules and their abundances in the prototypical photodissociation region (PDR) the Horsehead nebula to gain insight into sulphur chemistry in UV irradiated regions. Based on the WHISPER (Wide-band High-resolution Iram-30m Surveys at two positions with Emir Receivers) millimeter (mm) line survey, our goal is to provide an improved and more accurate description of sulphur species and their abundances towards the core and PDR positions in the Horsehead. METHODS The Monte Carlo Markov Chain (MCMC) methodology and the molecular excitation and radiative transfer code RADEX were used to explore the parameter space and determine physical conditions and beam-averaged molecular abundances. RESULTS A total of 13 S-bearing species (CS, SO, SO2, OCS, H2CS - both ortho and para - HDCS, C2S, HCS+, SO+, H2S, S2H, NS and NS+) have been detected in the two targeted positions. This is the first detection of SO+ in the Horsehead and the first detection of NS+ in any PDR. We find a differentiated chemical behaviour between C-S and O-S bearing species within the nebula. The C-S bearing species C2S and o-H2CS present fractional abundances a factor of > two higher in the core than in the PDR. In contrast, the O-S bearing molecules SO, SO2, and OCS present similar abundances towards both positions. A few molecules, SO+, NS, and NS+, are more abundant towards the PDR than towards the core, and could be considered as PDR tracers. CONCLUSIONS This is the first complete study of S-bearing species towards a PDR. Our study shows that CS, SO, and H2S are the most abundant S-bearing molecules in the PDR with abundances of ∼ a few 10-9. We recall that SH, SH+, S, and S+ are not observable at the wavelengths covered by the WHISPER survey. At the spatial scale of our observations, the total abundance of S atoms locked in the detected species is < 10-8, only ∼0.1% of the cosmic sulphur abundance.
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Affiliation(s)
- P Rivière-Marichalar
- Instituto de Física Fundamental (CSIC), Calle Serrano 121, 28006 Madrid, Spain
- Observatorio Astronómico Nacional (OAN,IGN), Apdo 112, E-28803 Alcalá de Henares, Spain
| | - A Fuente
- Observatorio Astronómico Nacional (OAN,IGN), Apdo 112, E-28803 Alcalá de Henares, Spain
| | - J R Goicoechea
- Instituto de Física Fundamental (CSIC), Calle Serrano 121, 28006 Madrid, Spain
| | - J Pety
- Institut de Radioastronomie Millimétrique (IRAM), 300 rue de la Piscine, 38406 Saint Martin d'Hères, France
- LERMA, Observatoire de Paris, PSL Research University, CNRS, Sorbonne Universités, UPMC Univ. Paris 06, Ecole Normale Supérieure, F-75005 Paris, France
| | - R Le Gal
- Harvard-Smithsonian Center for Astrophysics, 60 Garden St., Cambridge, MA 02138, USA
| | - P Gratier
- Laboratoire d'Astrophysique de Bordeaux, Univ. Bordeaux, CNRS, B18N, allée Geoffroy Saint-Hilaire, 33615 Pessac, France
| | - V Guzmán
- Instituto de Astrofísica, Pontificia Universidad Católica de Chile, Av. Vicunña Mackenna, 4860, 7820436, Macul, Santiago, Chile
| | - E Roueff
- LERMA, Observatoire de Paris, PSL Research University, CNRS, Sorbonne Universités, UPMC Univ. Paris 06, F-92190 Meudon, France
| | - J C Loison
- Institut des Sciences Moléculaires de Bordeaux (ISM), CNRS, Univ. Bordeaux, 351 cours de la Libération, 33400, Talence, France
| | - V Wakelam
- Laboratoire d'Astrophysique de Bordeaux, Univ. Bordeaux, CNRS, B18N, allée Geoffroy Saint-Hilaire, 33615 Pessac, France
| | - M Gerin
- LERMA, Observatoire de Paris, PSL Research University, CNRS, Sorbonne Universités, UPMC Univ. Paris 06, Ecole Normale Supérieure, F-75005 Paris, France
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Agúndez M, Marcelino N, Cernicharo J, Roueff E, Tafalla M. A sensitive λ 3 mm line survey of L483: A broad view of the chemical composition of a core around a Class 0 object. Astron Astrophys 2019; 625:A147. [PMID: 31327870 PMCID: PMC6640051 DOI: 10.1051/0004-6361/201935164] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
An exhaustive chemical characterization of dense cores is mandatory to our understanding of chemical composition changes from a starless to a protostellar stage. However, only a few sources have had their molecular composition characterized in detail. Here we present a λ 3 mm line survey of L483, a dense core around a Class 0 protostar, which was observed with the IRAM 30m telescope in the 80-116 GHz frequency range. We detected 71 molecules (140 including different isotopologs), most of which are present in the cold and quiescent ambient cloud according to their narrow lines (FWHM ~0.5 km s-1) and low rotational temperatures (≲10 K). Of particular interest among the detected molecules are the cis isomer of HCOOH, the complex organic molecules HCOOCH3, CH3OCH3, and C2H5OH, a wide variety of carbon chains, nitrogen oxides like N2O, and saturated molecules like CH3SH, in addition to eight new interstellar molecules (HCCO, HCS, HSC, NCCNH+, CNCN, NCO, H2NCO+, and NS+) whose detection has already been reported. In general, fractional molecular abundances in L483 are systematically lower than in TMC-1 (especially for carbon chains), tend to be higher than in L1544 and B1-b, and are similar to those in L1527. Apart from the overabundance of carbon chains in TMC-1, we find that L483 does not have a marked chemical differentiation with respect to starless/prestellar cores like TMC-1 and L1544, although it does chemically differentiate from Class 0 hot corino sources like IRAS 16293-2422. This fact suggests that the chemical composition of the ambient cloud of some Class 0 sources could be largely inherited from the dark cloud starless/prestellar phase. We explore the use of potential chemical evolutionary indicators, such as the HNCO/C3S, SO2/C2S, and CH3SH/C2S ratios, to trace the prestellar/protostellar transition. We also derived isotopic ratios for a variety of molecules, many of which show isotopic ratios close to the values for the local interstellar medium (remarkably all those involving 34S and 33S), while there are also several isotopic anomalies like an extreme depletion in 13C for one of the two isotopologs of c-C3H2, a drastic enrichment in 18O for SO and HNCO (SO being also largely enriched in 17O), and different abundances for the two 13C substituted species of C2H and the two 15N substituted species of N2H+. We report the first detection in space of some minor isotopologs like c-C3D. The exhaustive chemical characterization of L483 presented here, together with similar studies of other prestellar and protostellar sources, should allow us to identify the main factors that regulate the chemical composition of cores along the process of formation of low-mass protostars.
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Affiliation(s)
- M Agúndez
- Instituto de Física Fundamental, CSIC, C/ Serrano 123, E-28006 Madrid, Spain
| | - N Marcelino
- Instituto de Física Fundamental, CSIC, C/ Serrano 123, E-28006 Madrid, Spain
| | - J Cernicharo
- Instituto de Física Fundamental, CSIC, C/ Serrano 123, E-28006 Madrid, Spain
| | - E Roueff
- Sorbonne Université, Observatoire de Paris, Université PSL, CNRS, LERMA, F-92190 Meudon, France
| | - M Tafalla
- Observatorio Astronómico Nacional, C/ Alfonso XII 3, E-28014 Madrid, Spain
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Fuente A, Navarro DG, Caselli P, Gerin M, Kramer C, Roueff E, Alonso-Albi T, Bachiller R, Cazaux S, Commercon B, Friesen R, García-Burillo S, Giuliano BM, Goicoechea JR, Gratier P, Hacar A, Jiménez-Serra I, Kirk J, Lattanzi V, Loison JC, Malinen J, Marcelino N, Martín-Doménech R, Muñoz-Caro G, Pineda J, Tafalla M, Tercero B, Ward-Thompson D, Treviño-Morales SP, Riviére-Marichalar P, Roncero O, Vidal T, Ballester MY. Gas phase Elemental abundances in Molecular cloudS (GEMS): I. The prototypical dark cloud TMC 1. Astron Astrophys 2019; 624:10.1051/0004-6361/201834654. [PMID: 31156252 PMCID: PMC6542666 DOI: 10.1051/0004-6361/201834654] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
GEMS is an IRAM 30m Large Program whose aim is determining the elemental depletions and the ionization fraction in a set of prototypical star-forming regions. This paper presents the first results from the prototypical dark cloud TMC 1. Extensive millimeter observations have been carried out with the IRAM 30m telescope (3 mm and 2 mm) and the 40m Yebes telescope (1.3 cm and 7 mm) to determine the fractional abundances of CO, HCO+, HCN, CS, SO, HCS+, and N2H+ in three cuts which intersect the dense filament at the well-known positions TMC 1-CP, TMC 1-NH3, and TMC 1-C, covering a visual extinction range from A V ~ 3 to ~20 mag. Two phases with differentiated chemistry can be distinguished: i) the translucent envelope with molecular hydrogen densities of 1-5×103 cm-3; and ii) the dense phase, located at A V > 10 mag, with molecular hydrogen densities >104 cm-3. Observations and modeling show that the gas phase abundances of C and O progressively decrease along the C+/C/CO transition zone (A V ~ 3 mag) where C/H ~ 8×10-5 and C/O~0.8-1, until the beginning of the dense phase at A V ~ 10 mag. This is consistent with the grain temperatures being below the CO evaporation temperature in this region. In the case of sulfur, a strong depletion should occur before the translucent phase where we estimate a S/H ~ (0.4 - 2.2) ×10-6, an abundance ~7-40 times lower than the solar value. A second strong depletion must be present during the formation of the thick icy mantles to achieve the values of S/H measured in the dense cold cores (S/H ~8×10-8). Based on our chemical modeling, we constrain the value of ζ H2 to ~ (0.5 - 1.8) ×10-16 s-1 in the translucent cloud.
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Affiliation(s)
- A Fuente
- Observatorio Astronómico Nacional (OAN), Alfonso XII, 3, 28014, Madrid, Spain
| | - D G Navarro
- Observatorio Astronómico Nacional (OAN), Alfonso XII, 3, 28014, Madrid, Spain
| | - P Caselli
- Centre for Astrochemical Studies, Max-Planck-Institute for Extraterrestrial Physics, Giessenbachstrasse 1, 85748, Garching, Germany
| | - M Gerin
- Observatoire de Paris, PSL Research University, CNRS, École Normale Supérieure, Sorbonne Universités, UPMC Univ. Paris 06, 75005, Paris, France
| | - C Kramer
- Instituto Radioastronomía Milimétrica (IRAM), Av. Divina Pastora 7, Nucleo Central, 18012, Granada, Spain
| | - E Roueff
- Sorbonne Université, Observatoire de Paris, Université PSL, CNRS, LERMA, F-92190, Meudon, France
| | - T Alonso-Albi
- Observatorio Astronómico Nacional (OAN), Alfonso XII, 3, 28014, Madrid, Spain
| | - R Bachiller
- Observatorio Astronómico Nacional (OAN), Alfonso XII, 3, 28014, Madrid, Spain
| | - S Cazaux
- Faculty of Aerospace Engineering, Delft University of Technology, Delft, The Netherlands ; University of Leiden, P.O. Box 9513, NL, 2300 RA, Leiden, The Netherlands
| | - B Commercon
- École Normale Supérieure de Lyon, CRAL, UMR CNRS 5574, Université Lyon I, 46 Allée d'Italie, 69364, Lyon Cedex 07, France
| | - R Friesen
- National Radio Astronomy Observatory, 520 Edgemont Rd., Charlottesville VA USA 22901
| | - S García-Burillo
- Observatorio Astronómico Nacional (OAN), Alfonso XII, 3, 28014, Madrid, Spain
| | - B M Giuliano
- Centre for Astrochemical Studies, Max-Planck-Institute for Extraterrestrial Physics, Giessenbachstrasse 1, 85748, Garching, Germany
| | - J R Goicoechea
- Instituto de Física Fundamental (CSIC), Calle Serrano 123, 28006, Madrid, Spain
| | - P Gratier
- Laboratoire d'astrophysique de Bordeaux, Univ. Bordeaux, CNRS, B18N, allée Geoffroy Saint-Hilaire, 33615, Pessac, France
| | - A Hacar
- Leiden Observatory, Leiden University, PO Box 9513, 2300-RA, Leiden, The Netherlands
| | - I Jiménez-Serra
- Centro de Astrobiología (CSIC-INTA), Ctra. de Ajalvir, km 4, Torrejón de Ardoz, 28850, Madrid, Spain
| | - J Kirk
- Department of Physics, University of Warwick, Coventry CV4 7AL, UK
| | - V Lattanzi
- Centre for Astrochemical Studies, Max-Planck-Institute for Extraterrestrial Physics, Giessenbachstrasse 1, 85748, Garching, Germany
| | - J C Loison
- Institut des Sciences Moléculaires (ISM), CNRS, Univ. Bordeaux, 351 cours de la Libération, F-33400, Talence, France
| | - J Malinen
- Department of Physics, University of Helsinki, PO Box 64, 00014, Helsinki, Finland
- Institute of Physics I, University of Cologne, Cologne, Germany
| | - N Marcelino
- Instituto de Física Fundamental (CSIC), Calle Serrano 123, 28006, Madrid, Spain
| | - R Martín-Doménech
- Harvard-Smithsonian Center for Astrophysics, Cambridge, MA 02138, USA
| | - G Muñoz-Caro
- Centro de Astrobiología (CSIC-INTA), Ctra. de Ajalvir, km 4, Torrejón de Ardoz, 28850, Madrid, Spain
| | - J Pineda
- Centre for Astrochemical Studies, Max-Planck-Institute for Extraterrestrial Physics, Giessenbachstrasse 1, 85748, Garching, Germany
| | - M Tafalla
- Observatorio Astronómico Nacional (OAN), Alfonso XII, 3, 28014, Madrid, Spain
| | - B Tercero
- Observatorio Astronómico Nacional (OAN), Alfonso XII, 3, 28014, Madrid, Spain
| | - D Ward-Thompson
- Jeremiah Horrocks Institute, University of Central Lancashire, Preston PR1 2HE, UK
| | - S P Treviño-Morales
- Chalmers University of Technology, Department of Space, Earth and Environment, SE-412 93 Gothenburg, Sweden
| | | | - O Roncero
- Instituto de Física Fundamental (CSIC), Calle Serrano 123, 28006, Madrid, Spain
| | - T Vidal
- Laboratoire d'astrophysique de Bordeaux, Univ. Bordeaux, CNRS, B18N, allée Geoffroy Saint-Hilaire, 33615, Pessac, France
| | - Maikel Y Ballester
- Departamento de Física, Universidade Federal de Juiz de Fora-UFJF, Juiz de Fora, MG 36036-330, Brazil
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Molpeceres G, Rimola A, Ceccarelli C, Kästner J, Ugliengo P, Maté B. Silicate-mediated interstellar water formation: A theoretical study. Mon Not R Astron Soc 2019; 482:5389-5400. [PMID: 31156274 PMCID: PMC6544534 DOI: 10.1093/mnras/sty3024] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Water is one of the most abundant molecules in the form of solid ice phase in the different regions of the interstellar medium (ISM). This large abundance cannot be properly explained by using only traditional low temperature gas-phase reactions. Thus, surface chemical reactions are believed to be major synthetic channels for the formation of interstellar water ice. Among the different proposals, hydrogenation of atomic O (i.e., 2H + O → H2O) is a chemically "simple" and plausible reaction toward water formation occurring on the surfaces of interstellar grains. Here, novel theoretical results concerning the formation of water adopting this mechanism on the crystalline (010) Mg2SiO4 surface (a unequivocally identified interstellar silicate) are presented. The investigated reaction aims to simulate the formation of the first water ice layer covering the silicate core of dust grains. Adsorption of the atomic O as a first step of the reaction has been computed, results indicating that a peroxo (O 2 2 - ) group is formed. The following steps involve the adsorption, diffusion and reaction of two successive H atoms with the adsorbed O atom. Results indicate that H diffusion on the surface has barriers of 4-6 kcal mol-1, while actual formation of OH and H2O present energy barriers of 22-23 kcal mol-1. Kinetic study results show that tunneling is crucial for the occurrence of the reactions and that formation of OH and H2O are the bottlenecks of the overall process. Several astrophysical implications derived from the theoretical results are provided as concluding remarks.
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Affiliation(s)
- Germán Molpeceres
- Instituto de Estructura de la Materia, IEM-CSIC, Serrano 123, E-28006, Madrid, Spain
| | - Albert Rimola
- Departament de Química, Universitat Autònoma de Barcelona, 08193 Bellaterra, Spain
| | - Cecilia Ceccarelli
- Univ. Grenoble Alpes, CNRS, Institut de Planétologie et d’Astrophysique de Grenoble (IPAG), 38000 Grenoble, France
| | - Johannes Kästner
- Institute for Theoretical Chemistry, University of Stuttgart, Pfaffenwaldring 55, 70569 Stuttgart, Germany
| | - Piero Ugliengo
- Dipartimento di Chimica and Nanostructured Interfaces and Surfaces (NIS), Università degli Studi di Torino, Via P. Giuria 7, 10125 Torino, Italy
| | - Belén Maté
- Instituto de Estructura de la Materia, IEM-CSIC, Serrano 123, E-28006, Madrid, Spain
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Wenzel G, Castillo SR, Mulas G, Ji MC, Bonnamy A, Sabbah H, Giuliani A, Nahon L, Joblin C. Photoprocessing of large PAH cations. ACTA ACUST UNITED AC 2019; 15:388-9. [PMID: 33072171 DOI: 10.1017/S1743921319007063] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
In cosmic environments, polycyclic aromatic hydrocarbons (PAHs) strongly interact with vacuum ultraviolet (VUV) photons emitted by young stars. Trapped PAH cations ranging in size from 30 to 48 carbon atoms were irradiated by tunable synchrotron light (DESIRS beamline at SOLEIL). Their ionization and dissociation cross sections were determined and compared with TD-DFT computed photoabsorption cross sections. Evidence for radiative cooling is reported.
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Tercero B, Cuadrado S, López A, Brouillet N, Despois D, Cernicharo J. Chemical segregation of complex organic O-bearing species in Orion KL. Astron Astrophys 2018; 620:L6. [PMID: 31031406 PMCID: PMC6485672 DOI: 10.1051/0004-6361/201834417] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
We investigate the chemical segregation of complex O-bearing species (including the largest and most complex ones detected to date in space) towards Orion KL, the closest high-mass star-forming region. The molecular line images obtained using the ALMA science verification data reveal a clear segregation of chemically related species depending on their different functional groups. We map the emission of 13CH3OH, HCOOCH3, CH3OCH3, CH2OCH2, CH3COOCH3, HCOOCH2CH3, CH3CH2OCH3, HCOOH, OHCH2CH2OH, CH3COOH, CH3CH2OH, CH3OCH2OH, OHCH2CHO, and CH3COCH3 with ~1.5″ angular resolution and provide molecular abundances of these species toward different gas components of this region. We disentangle the emission of these species in the different Orion components by carefully selecting lines free of blending and opacity effects. Possible effects in the molecular spatial distribution due to residual blendings and different excitation conditions are also addressed. We find that while species containing the C-O-C group, i.e. an ether group, exhibit their peak emission and higher abundance towards the compact ridge, the hot core south is the component where species containing a hydroxyl group (-OH) bound to a carbon atom (C-O-H) present their emission peak and higher abundance. This finding allows us to propose methoxy (CH3O-) and hydroxymethyl (-CH2OH) radicals as the major drivers of the chemistry in the compact ridge and the hot core south, respectively, as well as different evolutionary stages and prevailing physical processes in the different Orion components.
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Affiliation(s)
- B Tercero
- Observatorio Astronómico Nacional (OAN-IGN). Calle Alfonso XII, 3, E-28014 Madrid, Spain
| | - S Cuadrado
- Instituto de Física Fundamental (IFF-CSIC). Calle Serrano 123, E-28006 Madrid, Spain
| | - A López
- Instituto de Física Fundamental (IFF-CSIC). Calle Serrano 123, E-28006 Madrid, Spain
| | - N Brouillet
- Laboratoire d'astrophysique de Bordeaux, Univ. Bordeaux, CNRS, B18N, alle Geoffroy Saint-Hilaire, 33615 Pessac, France
| | - D Despois
- Laboratoire d'astrophysique de Bordeaux, Univ. Bordeaux, CNRS, B18N, alle Geoffroy Saint-Hilaire, 33615 Pessac, France
| | - J Cernicharo
- Instituto de Física Fundamental (IFF-CSIC). Calle Serrano 123, E-28006 Madrid, Spain
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Bermúdez C, Tercero B, Motiyenko RA, Margulès L, Cernicharo J, Ellinger Y, Guillemin JC. The millimeter-wave spectrum of methyl ketene and the astronomical search for it. Astron Astrophys 2018; 619:A92. [PMID: 30595605 PMCID: PMC6309256 DOI: 10.1051/0004-6361/201833267] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
CONTEXT The analysis of isomeric species of a compound observed in the interstellar medium (ISM) is a useful tool to understand the chemistry of complex organic molecules. It could, likewise, assist in the detection of new species. AIMS Our goal consists in analyzing one of the two most stable species of the C3H4O family, methyl ketene, whose actual rotational parameters are not precise enough to allow its detection in the ISM. The obtained parameters will be used to search for it in the high-mass star-forming regions Orion KL and Sagittarius B2, as well as in the cold dark clouds TMC-1 in the Taurus Molecular Cloud and Barnard 1 (B1-b). METHODS A millimeter-wave room-temperature rotational spectrum of methyl ketene was recorded from 50 to 330 GHz. The internal rotation analysis of its ground state and first torsional excited state was performed with the rho-axis method employing the RAM36 program. RESULTS More than 3000 transitions of the rotational spectrum of the ground state (Kamax = 18) and first torsional excited state (Kamax = 13) of methyl ketene were fitted using a Hamiltonian that contains 41 parameters with an RMS (root mean square) of 41 kHz. Column density limits were calculated but no lines were detected in the ISM belonging to methyl ketene.
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Affiliation(s)
- C Bermúdez
- Université de Lille, Faculté des Sciences et Technologies, Département Physique, Laboratoire de Physique des Lasers, Atomes et Molécules, UMR CNRS 8523, 59655 Villeneuve d'Ascq Cedex, France
| | - B Tercero
- Observatorio Astronómico Nacional (IGN), C/Alfonso XII 3, 28014 Madrid, Spain
| | - R A Motiyenko
- Université de Lille, Faculté des Sciences et Technologies, Département Physique, Laboratoire de Physique des Lasers, Atomes et Molécules, UMR CNRS 8523, 59655 Villeneuve d'Ascq Cedex, France
| | - L Margulès
- Université de Lille, Faculté des Sciences et Technologies, Département Physique, Laboratoire de Physique des Lasers, Atomes et Molécules, UMR CNRS 8523, 59655 Villeneuve d'Ascq Cedex, France
| | - J Cernicharo
- Instituto de Física Fundamental, Dpt. of Molecular Astrophysics, CSIC, C/ Serrano 121, 28006, Madrid, Spain
| | - Y Ellinger
- Sorbone Université, CNRS, Laboratoire de Chimie Théorique, LCT, F. 75005 Paris, France
| | - J-C Guillemin
- Univ. Rennes, Ecole Nationale Supérieure de Chimie de Rennes, CNRS, ISCR - UMR6226, F-35000 Rennes, France
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Kolesniková L, Peña I, Alonso ER, Tercero B, Cernicharo J, Mata S, Alonso JL. Laboratory rotational spectrum and astronomical search for methoxyacetaldehyde. Astron Astrophys 2018; 619:A67. [PMID: 30555173 PMCID: PMC6290985 DOI: 10.1051/0004-6361/201833773] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
CONTEXT Methoxyacetaldehyde belongs to a group of structural isomers with the general formula C3H6O2, of which methyl acetate and ethyl formate are known interstellar molecules. Rotational data available for methoxyacetaldehyde are limited to 40 GHz, which makes predictions at higher frequencies rather uncertain. AIMS The aim of this work is to provide accurate experimental frequencies of methoxyacetaldehyde in the millimeter-wave region to support its detection in the interstellar medium. METHODS The rotational spectrum of methoxyacetaldehyde was recorded at room-temperature from 75 to 120 GHz and from 170 to 310 GHz using the millimeter-wave spectrometer in Valladolid. Additional measurements were also performed at conditions of supersonic expansion from 6 to 18 GHz. The assigned rotational transitions were analyzed using the S -reduced semirigid-rotor Hamiltonian. RESULTS We newly assigned over 1000 lines for the most stable conformer of methoxyacetaldehyde in its ground state and five lowest excited vibrational states, and precise sets of spectroscopic constants were obtained. We searched for spectral features of methoxyacetaldehyde in the high-mass star-forming regions Orion KL and Sagittarius B2, as well as in the cold dark cloud Barnard 1 (B1-b). No lines belonging to methoxyacetaldehyde were detected above the detection limit of our data. We provide upper limits to the methoxyacetaldehyde colum density in these sources.
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Affiliation(s)
- L Kolesniková
- Grupo de Espectroscopia Molecular (GEM), Edificio Quifima, Área de Química-Física, Laboratorios de Espectroscopia y Bioespectroscopia, Parque Científico UVa, Unidad Asociada CSIC, Universidad de Valladolid, 47011 Valladolid, Spain
| | - I Peña
- Grupo de Espectroscopia Molecular (GEM), Edificio Quifima, Área de Química-Física, Laboratorios de Espectroscopia y Bioespectroscopia, Parque Científico UVa, Unidad Asociada CSIC, Universidad de Valladolid, 47011 Valladolid, Spain
| | - E R Alonso
- Grupo de Espectroscopia Molecular (GEM), Edificio Quifima, Área de Química-Física, Laboratorios de Espectroscopia y Bioespectroscopia, Parque Científico UVa, Unidad Asociada CSIC, Universidad de Valladolid, 47011 Valladolid, Spain
| | - B Tercero
- Observatorio Astronómico Nacional (OAN-IGN), Calle Alfonso XII 3, 28014 Madrid, Spain
| | - J Cernicharo
- Instituto de Física Fundamental (IFF-CSIC), Calle Serrano 123, 28006 Madrid, Spain
| | - S Mata
- Grupo de Espectroscopia Molecular (GEM), Edificio Quifima, Área de Química-Física, Laboratorios de Espectroscopia y Bioespectroscopia, Parque Científico UVa, Unidad Asociada CSIC, Universidad de Valladolid, 47011 Valladolid, Spain
| | - J L Alonso
- Grupo de Espectroscopia Molecular (GEM), Edificio Quifima, Área de Química-Física, Laboratorios de Espectroscopia y Bioespectroscopia, Parque Científico UVa, Unidad Asociada CSIC, Universidad de Valladolid, 47011 Valladolid, Spain
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Abstract
We report rest frequencies for rotational transitions of the deuterated ammonium isotopologues NH3D+,NH 2 D 2 + and NHD D 3 + , measured in a cryogenic ion trap machine. For the symmetric tops NH3D+ andNHD 3 + one and three transitions are detected, respectively, and five transitions are detected for the asymmetric topNH 2 D 2 + . While the lowest frequency transition of NH3D+ was already known in the laboratory and space, this work enables the future radio astronomical detection of the two other isotopologues.
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Affiliation(s)
- José L. Doménech
- Instituto de Estructura de la Materia (IEM-CSIC), Serrano
123, E28006 Madrid, Spain
| | - Stephan Schlemmer
- I. Physikalisches Institut, Universität zu
Köln, Zülpicher Str. 77, 50937 Köln, Germany
| | - Oskar Asvany
- I. Physikalisches Institut, Universität zu
Köln, Zülpicher Str. 77, 50937 Köln, Germany
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Goicoechea JR, Pety J, Chapillon E, Cernicharo J, Gerin M, Herrera C, Requena-Torres MA, Santa-Maria MG. High-speed molecular cloudlets around the Galactic center's supermassive black hole. Astron Astrophys 2018; 618:A35. [PMID: 30429617 PMCID: PMC6231548 DOI: 10.1051/0004-6361/201833558] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
We present 1″-resolution ALMA observations of the circumnuclear disk (CND) and the interstellar environment around Sgr A*. The images unveil the presence of small spatial scale 12CO (J=3-2) molecular "cloudlets" (≲20,000 AU size) within the central parsec of the Milky Way, in other words, inside the cavity of the CND, and moving at high speeds, up to 300 km s-1 along the line-of-sight. The 12CO-emitting structures show intricate morphologies: extended and filamentary at high negative-velocities (vLSR ≲-150 km s-1), more localized and clumpy at extreme positive-velocities (vLSR ≳+200 km s-1). Based on the pencil-beam 12CO absorption spectrum toward Sgr A* synchrotron emission, we also present evidence for a diffuse molecular gas component producing absorption features at more extreme negative-velocities (vLSR <-200 km s-1). The CND shows a clumpy spatial distribution traced by the optically thin H13CN (J=4-3) emission. Its motion requires a bundle of non-uniformly rotating streams of slightly different inclinations. The inferred gas density peaks, molecular cores of a few 105 cm-3, are lower than the local Roche limit. This supports that CND cores are transient. We apply the two standard orbit models, spirals vs. ellipses, invoked to explain the kinematics of the ionized gas streamers around Sgr A*. The location and velocities of the 12CO cloudlets inside the cavity are inconsistent with the spiral model, and only two of them are consistent with the Keplerian ellipse model. Most cloudlets, however, show similar velocities that are incompatible with the motions of the ionized streamers or with gas bounded to the central gravity. We speculate that they are leftovers of more massive molecular clouds that fall into the cavity and are tidally disrupted, or that they originate from instabilities in the inner rim of the CND that lead to fragmentation and infall from there. In either case, we show that molecular cloudlets, all together with a mass of several 10 M ⊙, exist around Sgr A*. Most of them must be short-lived, ≲104 yr: photoevaporated by the intense stellar radiation field, G 0≃105.3 to 104.3, blown away by winds from massive stars in the central cluster, or disrupted by strong gravitational shears.
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Affiliation(s)
- Javier R Goicoechea
- Instituto de Física Fundamental (CSIC). Calle Serrano 121, 28006, Madrid, Spain
| | - Jerome Pety
- Institut de Radioastronomie Millimétrique (IRAM), 300 rue de la Piscine, F-38406 Saint Martin d'Hères, France
- Sorbonne Université, Observatoire de Paris, Université PSL, École Normale Supérieure, CNRS, LERMA, F-75014, Paris, France
| | - Edwige Chapillon
- Institut de Radioastronomie Millimétrique (IRAM), 300 rue de la Piscine, F-38406 Saint Martin d'Hères, France
- OASU/LAB-UMR5804, CNRS, Université Bordeaux, allée Geoffroy Saint-Hilaire, 33615 Pessac, France
| | - José Cernicharo
- Instituto de Física Fundamental (CSIC). Calle Serrano 121, 28006, Madrid, Spain
| | - Maryvonne Gerin
- Sorbonne Université, Observatoire de Paris, Université PSL, École Normale Supérieure, CNRS, LERMA, F-75014, Paris, France
| | - Cinthya Herrera
- Institut de Radioastronomie Millimétrique (IRAM), 300 rue de la Piscine, F-38406 Saint Martin d'Hères, France
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39
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Kolesniková L, Alonso ER, Tercero B, Cernicharo J, Alonso JL. Millimeter wave spectra of ethyl isocyanate and searches for it in Orion KL and Sgr B2. Astron Astrophys 2018; 616:A173. [PMID: 30369619 PMCID: PMC6203308 DOI: 10.1051/0004-6361/201833223] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
CONTEXT Relatively high abundances of methyl isocyanate (CH3NCO), a methyl derivative of isocyanic acid (HNCO), found in the Orion KL and Sgr B2 molecular clouds suggest that its ethyl derivative, ethyl isocyanate (CH3CH2NCO), may also be present. AIMS The aim of this work is to provide accurate experimental frequencies of ethyl isocyanate in its ground and excited vibrational states in the millimeter wave region to support searches for it in the interstellar medium. METHODS The rotational spectrum of ethyl isocyanate was recorded at room temperature from 80 to 340 GHz using the millimeter wave spectrometer in Valladolid. Assigned rotational transitions were analyzed using the S -reduced semirigid-rotor Hamiltonian. RESULTS More than 1100 distinct frequency lines were analyzed for the ground vibrational state of the cis conformer as well as for three vibrational satellites corresponding to successive excitation of the lowest-energy C-N torsional mode. Newly determined rotational and centrifugal distortion constants were used for searches of spectral features of ethyl isocyanate in Orion KL and Sgr B2 clouds. Upper limits to CH3CH2NCO in these high-mass star-forming regions were obtained.
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Affiliation(s)
- L Kolesniková
- Grupo de Espectroscopia Molecular (GEM), Edificio Quifima, Área de Química-Física, Laboratorios de Espectroscopia y Bioespectroscopia, Parque Científico UVa, Unidad Asociada CSIC, Universidad de Valladolid, E-47011 Valladolid, Spain
| | - E R Alonso
- Grupo de Espectroscopia Molecular (GEM), Edificio Quifima, Área de Química-Física, Laboratorios de Espectroscopia y Bioespectroscopia, Parque Científico UVa, Unidad Asociada CSIC, Universidad de Valladolid, E-47011 Valladolid, Spain
| | - B Tercero
- Observatorio Astronómico Nacional (OAN-IGN). Calle Alfonso XII, 3, E-28014 Madrid, Spain
| | - J Cernicharo
- Instituto de Ciencia de Materiales de Madrid, CSIC, C/ Sor Juana Inés de la Cruz 3,E-28049 Cantoblanco, Spain
| | - J L Alonso
- Grupo de Espectroscopia Molecular (GEM), Edificio Quifima, Área de Química-Física, Laboratorios de Espectroscopia y Bioespectroscopia, Parque Científico UVa, Unidad Asociada CSIC, Universidad de Valladolid, E-47011 Valladolid, Spain
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40
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Goicoechea JR, Santa-Maria MG, Teyssier D, Cernicharo J, Gerin M, Pety J. High-velocity hot CO emission close to Sgr A*: Herschel/HIFI ★ , ★★ submillimeter spectral survey toward Sgr A. Astron Astrophys 2018; 616:L1. [PMID: 31844332 PMCID: PMC6914365 DOI: 10.1051/0004-6361/201833684] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
The properties of molecular gas, the fuel that forms stars, inside the cavity of the circumnuclear disk (CND) are not well constrained. We present results of a velocity-resolved submillimeter scan (~480 to 1250 GHz) and [C ii] 158 μm line observations carried out with Herschel/HIFI toward Sgr A*; these results are complemented by a ~2'×2' 12CO (J=3-2) map taken with the IRAM 30 m telescope at ~7″ resolution. We report the presence of high positive-velocity emission (up to about +300 km s-1) detected in the wings of 12CO J=5-4 to 10-9 lines. This wing component is also seen in H2O (11,0-10,1), a tracer of hot molecular gas; in [C ii]158 μm, an unambiguous tracer of UV radiation; but not in [C i] 492, 806 GHz. This first measurement of the high-velocity 12CO rotational ladder toward Sgr A* adds more evidence that hot molecular gas exists inside the cavity of the CND, relatively close to the supermassive black hole (< 1 pc). Observed by ALMA, this velocity range appears as a collection of 12CO (J=3-2) cloudlets lying in a very harsh environment that is pervaded by intense UV radiation fields, shocks, and affected by strong gravitational shears. We constrain the physical conditions of the high positive-velocity CO gas component by comparing with non-LTE excitation and radiative transfer models. We infer T k≃400 K to 2000 K for n H≃(0.2-1.0)·105 cm-3. These results point toward the important role of stellar UV radiation, but we show that radiative heating alone cannot explain the excitation of this ~10-60 M ⊙ component of hot molecular gas inside the central cavity. Instead, strongly irradiated shocks are promising candidates.
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Affiliation(s)
- J R Goicoechea
- Instituto de Física Fundamental (CSIC). Calle Serrano 121, 28006, Madrid, Spain
| | - M G Santa-Maria
- Instituto de Física Fundamental (CSIC). Calle Serrano 121, 28006, Madrid, Spain
| | - D Teyssier
- Telespazio Vega UK Ltd for ESA/ESAC. Urbanización Villafranca del Castillo, Villanueva de la Cañada, E-28692 Madrid, Spain
| | - J Cernicharo
- Instituto de Física Fundamental (CSIC). Calle Serrano 121, 28006, Madrid, Spain
| | - M Gerin
- Sorbonne Université, Observatoire de Paris, Université PSL, École Normale Supérieure, CNRS, LERMA, F-75014, Paris, France
| | - J Pety
- Sorbonne Université, Observatoire de Paris, Université PSL, École Normale Supérieure, CNRS, LERMA, F-75014, Paris, France
- Institut de Radioastronomie Millimétrique (IRAM), 300 rue de la Piscine, F-38406 Saint Martin d'Hères, France
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41
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Agúndez M, Marcelino N, Cernicharo J. Discovery of Interstellar Isocyanogen (CNCN): Further Evidence that Dicyanopolyynes are Abundant in Space. Astrophys J Lett 2018; 861:L22. [PMID: 30186588 PMCID: PMC6120679 DOI: 10.3847/2041-8213/aad089] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
It is thought that dicyanopolyynes could be potentially abundant interstellar molecules, although their lack of dipole moment makes it impossible to detect them through radioastronomical techniques. Recently, the simplest member of this chemical family, cyanogen (NCCN), was indirectly probed for the first time in interstellar space through the detection of its protonated form toward the dense clouds L483 and TMC-1. Here we present a second firm evidence of the presence of NCCN in interstellar space, namely the detection of the metastable and polar isomer isocyanogen (CNCN). This species has been identified in L483 and tentatively in TMC-1 by observing various rotational transitions in the λ 3 mm band with the IRAM 30m telescope. We derive beam-averaged column densities for CNCN of 1.6 × 1012 cm-2 in L483 and 9 × 1011 cm-2 in TMC-1, which imply fractional abundances relative to H2 in the range (5 - 9) × 10-11. While the presence of NCCN in interstellar clouds seems out of doubt owing to the detection of NCCNH+ and CNCN, putting tight constraints on its abundance is still hampered by the poor knowledge of the chemistry that links NCCN with NCCNH+ and especially with CNCN. We estimate that NCCN could be fairly abundant, in the range 10-9-10-7 relative to H2, as other abundant nitriles like HCN and HC3N.
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Affiliation(s)
- M Agúndez
- Instituto de Física Fundamental, CSIC, C/ Serrano 123, 28006 Madrid, Spain
| | - N Marcelino
- Instituto de Física Fundamental, CSIC, C/ Serrano 123, 28006 Madrid, Spain
| | - J Cernicharo
- Instituto de Física Fundamental, CSIC, C/ Serrano 123, 28006 Madrid, Spain
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Agúndez M, Marcelino N, Cernicharo J, Tafalla M. Detection of interstellar HCS and its metastable isomer HSC: new pieces in the puzzle of sulfur chemistry. Astron Astrophys 2018; 611:L1. [PMID: 29983448 PMCID: PMC6031296 DOI: 10.1051/0004-6361/201832743] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
Abstract
We present the first identification in interstellar space of the thioformyl radical (HCS) and its metastable isomer HSC. These species were detected toward the molecular cloud L483 thanks to observations carried out with the IRAM 30m telescope in the λ 3 mm band. We derive beam-averaged column densities of 7 × 1012 cm-2 for HCS and 1.8 × 1011 cm-2 for HSC, which translate to fractional abundances relative to H2 of 2 × 10-10 and 6 × 10-12, respectively. Although the amount of sulfur locked by these radicals is low, their detection allows to put interesting constraints on the chemistry of sulfur in dark clouds. Interestingly, the H2CS/HCS abundance ratio is found to be quite low, ~ 1, in contrast with the oxygen analogue case, in which the H2CO/HCO abundance ratio is around 10 in dark clouds. Moreover, the radical HCS is found to be more abundant than its oxygen analogue, HCO. The metastable species HOC, the oxygen analogue of HSC, has not been yet observed in space. These observational constraints are confronted with the outcome of a recent model of the chemistry of sulfur in dark clouds. The model underestimates the fractional abundance of HCS by at least one order of magnitude, overestimates the H2CS/HCS abundance ratio, and does not provide an abundance prediction for the metastable isomer HSC. These observations should prompt a revision of the chemistry of sulfur in interstellar clouds.
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Affiliation(s)
- M Agúndez
- Instituto de Física Fundamental, CSIC, C/ Serrano 123, 28006 Madrid, Spain
| | - N Marcelino
- Instituto de Física Fundamental, CSIC, C/ Serrano 123, 28006 Madrid, Spain
| | - J Cernicharo
- Instituto de Física Fundamental, CSIC, C/ Serrano 123, 28006 Madrid, Spain
| | - M Tafalla
- Observatorio Astronómico Nacional (OAN), C/ Alfonso XII 3, 28014 Madrid, Spain
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43
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Bron E, Daudon C, Pety J, Levrier F, Gerin M, Gratier P, Orkisz JH, Guzman V, Bardeau S, Goicoechea JR, Liszt H, Öberg K, Peretto N, Sievers A, Tremblin P. Clustering the Orion B giant molecular cloud based on its molecular emission. Astron Astrophys 2018; 610:A12. [PMID: 29456256 PMCID: PMC5813791 DOI: 10.1051/0004-6361/201731833] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
CONTEXT Previous attempts at segmenting molecular line maps of molecular clouds have focused on using position-position-velocity data cubes of a single molecular line to separate the spatial components of the cloud. In contrast, wide field spectral imaging over a large spectral bandwidth in the (sub)mm domain now allows one to combine multiple molecular tracers to understand the different physical and chemical phases that constitute giant molecular clouds (GMCs). AIMS We aim at using multiple tracers (sensitive to different physical processes and conditions) to segment a molecular cloud into physically/chemically similar regions (rather than spatially connected components), thus disentangling the different physical/chemical phases present in the cloud. METHODS We use a machine learning clustering method, namely the Meanshift algorithm, to cluster pixels with similar molecular emission, ignoring spatial information. Clusters are defined around each maximum of the multidimensional Probability Density Function (PDF) of the line integrated intensities. Simple radiative transfer models were used to interpret the astrophysical information uncovered by the clustering analysis. RESULTS A clustering analysis based only on the J = 1 - 0 lines of three isotopologues of CO proves suffcient to reveal distinct density/column density regimes (nH ~ 100 cm-3, ~ 500 cm-3, and > 1000 cm-3), closely related to the usual definitions of diffuse, translucent and high-column-density regions. Adding two UV-sensitive tracers, the J = 1 - 0 line of HCO+ and the N = 1 - 0 line of CN, allows us to distinguish two clearly distinct chemical regimes, characteristic of UV-illuminated and UV-shielded gas. The UV-illuminated regime shows overbright HCO+ and CN emission, which we relate to a photochemical enrichment effect. We also find a tail of high CN/HCO+ intensity ratio in UV-illuminated regions. Finer distinctions in density classes (nH ~ 7 × 103 cm-3 ~ 4 × 104 cm-3) for the densest regions are also identified, likely related to the higher critical density of the CN and HCO+ (1 - 0) lines. These distinctions are only possible because the high-density regions are spatially resolved. CONCLUSIONS Molecules are versatile tracers of GMCs because their line intensities bear the signature of the physics and chemistry at play in the gas. The association of simultaneous multi-line, wide-field mapping and powerful machine learning methods such as the Meanshift clustering algorithm reveals how to decode the complex information available in these molecular tracers.
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Affiliation(s)
- Emeric Bron
- ICMM, Consejo Superior de Investigaciones Cientificas (CSIC). E-28049. Madrid, Spain
- LERMA, Observatoire de Paris, PSL Research University, CNRS, Sorbonne Universités, UPMC Univ. Paris 06, 92190 Meudon, France
| | - Chloé Daudon
- LERMA, Observatoire de Paris, PSL Research University, CNRS, Sorbonne Universités, UPMC Univ. Paris 06, École normale supérieure, 75005 Paris, France
| | - Jérôme Pety
- IRAM, 300 rue de la Piscine, 38406 Saint Martin d'Hères, France
- LERMA, Observatoire de Paris, PSL Research University, CNRS, Sorbonne Universités, UPMC Univ. Paris 06, École normale supérieure, 75005 Paris, France
| | - François Levrier
- LERMA, Observatoire de Paris, PSL Research University, CNRS, Sorbonne Universités, UPMC Univ. Paris 06, École normale supérieure, 75005 Paris, France
| | - Maryvonne Gerin
- LERMA, Observatoire de Paris, PSL Research University, CNRS, Sorbonne Universités, UPMC Univ. Paris 06, École normale supérieure, 75005 Paris, France
| | - Pierre Gratier
- Laboratoire d'astrophysique de Bordeaux, Univ. Bordeaux, CNRS, B18N, allée Geoffroy Saint-Hilaire, 33615 Pessac, France
| | - Jan H Orkisz
- Univ. Grenoble Alpes, IRAM, 38000 Grenoble, France
- IRAM, 300 rue de la Piscine, 38406 Saint Martin d'Hères, France
- LERMA, Observatoire de Paris, PSL Research University, CNRS, Sorbonne Universités, UPMC Univ. Paris 06, École normale supérieure, 75005 Paris, France
| | - Viviana Guzman
- Joint ALMA Observatory (JAO), Alonso de Cordova 3107 Vitacura, Santiago de Chile, Chile
| | | | - Javier R Goicoechea
- ICMM, Consejo Superior de Investigaciones Cientificas (CSIC). E-28049. Madrid, Spain
| | - Harvey Liszt
- National Radio Astronomy Observatory, 520 Edgemont Road, Charlottesville, VA, 22903, USA
| | - Karin Öberg
- Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA, 02138, USA
| | - Nicolas Peretto
- School of Physics and Astronomy, Cardiff University, Queen's buildings, Cardiff CF24 3AA, UK
| | | | - Pascal Tremblin
- Maison de la Simulation, CEA-CNRS-INRIA-UPS-UVSQ, USR 3441, Centre d'étude de Saclay, F-91191 Gif-Sur-Yvette, France
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Melosso M, Melli A, Puzzarini C, Codella C, Spada L, Dore L, Degli Esposti C, Lefloch B, Bachiller R, Ceccarelli C, Cernicharo J, Barone V. Laboratory measurements and astronomical search for cyanomethanimine. Astron Astrophys 2018; 609:A121. [PMID: 30078846 PMCID: PMC6071866 DOI: 10.1051/0004-6361/201731972] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
CONTEXT C-cyanomethanimine (HNCHCN), existing in the two Z and E isomeric forms, is a key prebiotic molecule, but, so far, only the E isomer has been detected toward the massive star-forming region. Sagittarius B2(N) using transitions in the radio wavelength domain. AIMS With the aim of detecting HNCHCN in Sun-like-star forming regions, the laboratory investigation of its rotational spectrum has been extended to the millimeter-/submillimeter-wave (mm-/submm-) spectral window in which several unbiased spectral surveys have been already carried out. METHODS High-resolution laboratory measurements of the rotational spectrum of C-cyanomethanimine were carried out in the 100-420 GHz range using a frequency-modulation absorption spectrometer. We then searched for the C-cyanomethanimine spectral features in the mm-wave range using the high-sensitivity and unbiased spectral surveys obtained with the IRAM 30-m antenna in the ASAI context, the earliest stages of star formation from starless to evolved Class I objects being sampled. RESULTS For both the Z and E isomers, the spectroscopic work has led to an improved and extended knowledge of the spectroscopic parameters, thus providing accurate predictions of the rotational signatures up to ~700 GHz. So far, no C-cyanomethanimine emission has been detected toward the ASAI targets, and upper limits of the column density of ~ 1011-1012 cm-2 could only be derived. Consequently, the C-cyanomethanimine abundances have to be less than a few 10-10 for starless and hot-corinos. A less stringent constraint, ≤ 10-9, is obtained for shocks sites. CONCLUSIONS The combination of the upper limits of the abundances of C-cyanomethanimine together with accurate laboratory frequencies up to ~ 700 GHz poses the basis for future higher sensitivity searches around Sun-like-star forming regions. For compact (typically less than 1″) and chemically enriched sources such as hot-corinos, the use of interferometers as NOEMA and ALMA in their extended configurations are clearly needed.
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Affiliation(s)
- M. Melosso
- Dipartimento di Chimica “Giacomo Ciamician”, Università di Bologna, Via Selmi 2, I-40126 Bologna, Italy
| | - A. Melli
- Dipartimento di Chimica “Giacomo Ciamician”, Università di Bologna, Via Selmi 2, I-40126 Bologna, Italy
| | - C. Puzzarini
- Dipartimento di Chimica “Giacomo Ciamician”, Università di Bologna, Via Selmi 2, I-40126 Bologna, Italy
- INAF, Osservatorio Astonomico di Arcetri, Largo E. Fermi 5, 50125, Firenze, Italy
| | - C. Codella
- INAF, Osservatorio Astonomico di Arcetri, Largo E. Fermi 5, 50125, Firenze, Italy
| | - L. Spada
- Dipartimento di Chimica “Giacomo Ciamician”, Università di Bologna, Via Selmi 2, I-40126 Bologna, Italy
- Scuola Normale Superiore, Piazza dei Cavalieri 7, I-56126 Pisa, Italy
| | - L. Dore
- Dipartimento di Chimica “Giacomo Ciamician”, Università di Bologna, Via Selmi 2, I-40126 Bologna, Italy
| | - C. Degli Esposti
- Dipartimento di Chimica “Giacomo Ciamician”, Università di Bologna, Via Selmi 2, I-40126 Bologna, Italy
| | - B. Lefloch
- Univ. Grenoble Alpes, CNRS, Institut de Planétologie et d’Astrophysique de Grenoble (IPAG), 38000 Grenoble, France
| | - R. Bachiller
- IGN, Observatorio Astronómico Nacional, Calle Alfonso XII, 28004 Madrid, Spain
| | - C. Ceccarelli
- INAF, Osservatorio Astonomico di Arcetri, Largo E. Fermi 5, 50125, Firenze, Italy
- Univ. Grenoble Alpes, CNRS, Institut de Planétologie et d’Astrophysique de Grenoble (IPAG), 38000 Grenoble, France
| | - J. Cernicharo
- Grupo de Astrofísica Molecular. Instituto de CC. de Materiales de Madrid (ICMM-CSIC). Sor Juana Inés de la Cruz 3, Cantoblanco, 28049 Madrid, Spain
| | - V. Barone
- Scuola Normale Superiore, Piazza dei Cavalieri 7, I-56126 Pisa, Italy
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Turner AM, Abplanalp MJ, Blair TJ, Dayuha R, Kaiser RI. An Infrared Spectroscopic Study Toward the Formation of Alkylphosphonic Acids and Their Precursors in Extraterrestrial Environments. Astrophys J Suppl Ser 2018; 234:6. [PMID: 30842689 PMCID: PMC6398957 DOI: 10.3847/1538-4365/aa9183] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
The only known phosphorus-containing organic compounds of extraterrestrial origin, alkylphosphonic acids, were discovered in the Murchison meteorite and have accelerated the hypothesis that reduced oxidation states of phosphorus were delivered to early Earth and served as a prebiotic source of phosphorus. While previous studies looking into the formation of these alkylphosphonic acids have focused on the iron-nickel phosphide mineral schreibersite and phosphorous acid as a source of phosphorus, this work utilizes phosphine (PH3), which has been discovered in the circumstellar envelope of IRC +10216, in the atmosphere of Jupiter and Saturn, and believed to be the phosphorus carrier in comet 67P/Churyumov-Gerasimenko. Phosphine ices prepared with interstellar molecules such as carbon dioxide, water, and methane were subjected to electron irradiation, which simulates the secondary electrons produced from galactic cosmic rays penetrating the ice, and probed using infrared spectroscopy to understand the possible formation of alkylphosphonic acids and their precursors on interstellar icy grains that could become incorporated into meteorites such as Murchison. We present the first study and results on the possible synthesis of alkylphosphonic acids produced from phosphine-mixed ices under interstellar conditions. All functional groups of alkylphosphonic acids were detected through infrared spectroscopically, suggesting that this class of molecules can be formed in interstellar ices.
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Affiliation(s)
- Andrew M Turner
- W. M. Keck Research Laboratory in Astrochemistry, University of Hawaii at Manoa, Honolulu, Hawaii 96822, USA;
- Department of Chemistry, University of Hawaii at Manoa, Honolulu, Hawaii 96822, USA
| | - Matthew J Abplanalp
- W. M. Keck Research Laboratory in Astrochemistry, University of Hawaii at Manoa, Honolulu, Hawaii 96822, USA;
- Department of Chemistry, University of Hawaii at Manoa, Honolulu, Hawaii 96822, USA
| | - Tyler J Blair
- W. M. Keck Research Laboratory in Astrochemistry, University of Hawaii at Manoa, Honolulu, Hawaii 96822, USA;
- Department of Chemistry, University of Hawaii at Manoa, Honolulu, Hawaii 96822, USA
| | - Remwilyn Dayuha
- W. M. Keck Research Laboratory in Astrochemistry, University of Hawaii at Manoa, Honolulu, Hawaii 96822, USA;
- Department of Chemistry, University of Hawaii at Manoa, Honolulu, Hawaii 96822, USA
| | - Ralf I Kaiser
- W. M. Keck Research Laboratory in Astrochemistry, University of Hawaii at Manoa, Honolulu, Hawaii 96822, USA;
- Department of Chemistry, University of Hawaii at Manoa, Honolulu, Hawaii 96822, USA
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Kolesniková L, Tercero B, Alonso ER, Guillemin JC, Cernicharo J, Alonso JL. Rotational spectrum of methoxyamine up to 480 GHz: a laboratory study and astronomical search. Astron Astrophys 2018; 609:A24. [PMID: 29983447 PMCID: PMC6031297 DOI: 10.1051/0004-6361/201730744] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
Abstract
AIMS Methoxyamine is a potential interstellar amine that has been predicted by gas-grain chemical models for the formation of complex molecules. The aim of this work is to provide direct experimental frequencies of its ground-vibrational state in the millimeter- and submillimeter-wave regions to achieve its detection in the interstellar medium. METHODS Methoxyamine was chemically liberated from its hydrochloride salt, and its rotational spectrum was recorded at room temperature from 75 to 480 GHz using the millimeter-wave spectrometer in Valladolid. Many observed transitions revealed A-E splitting caused by the internal rotation of the methyl group, which had to be treated with specific internal rotation codes. RESULTS Over 400 lines were newly assigned for the most stable conformer of methoxyamine, and a precise set of spectroscopic constants was obtained. Spectral features of methoxyamine were then searched for in the Orion KL, Sgr B2, B1-b, and TMC-1 molecular clouds. Upper limits to the column density of methoxyamine were derived.
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Affiliation(s)
- L Kolesniková
- Grupo de Espectroscopia Molecular (GEM), Edificio Quifima, Área de Química-Física, Laboratorios de Espectroscopia y Bioespectroscopia, Parque Científico UVa, Unidad Asociada CSIC, Universidad de Valladolid, 47011 Valladolid, Spain
| | - B Tercero
- Instituto de Ciencia de Materiales de Madrid, CSIC, C/ Sor Juana Inés de la Cruz 3, 28049 Cantoblanco, Spain
| | - E R Alonso
- Grupo de Espectroscopia Molecular (GEM), Edificio Quifima, Área de Química-Física, Laboratorios de Espectroscopia y Bioespectroscopia, Parque Científico UVa, Unidad Asociada CSIC, Universidad de Valladolid, 47011 Valladolid, Spain
| | - J-C Guillemin
- Institut des Sciences Chimiques de Rennes, École Nationale Supérieure de Chimie de Rennes, CNRS, UMR 6226, 11 Allée de Beaulieu, CS 50837, 35708 Rennes Cedex 7, France
| | - J Cernicharo
- Instituto de Ciencia de Materiales de Madrid, CSIC, C/ Sor Juana Inés de la Cruz 3, 28049 Cantoblanco, Spain
| | - J L Alonso
- Grupo de Espectroscopia Molecular (GEM), Edificio Quifima, Área de Química-Física, Laboratorios de Espectroscopia y Bioespectroscopia, Parque Científico UVa, Unidad Asociada CSIC, Universidad de Valladolid, 47011 Valladolid, Spain
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47
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Fuente A, Goicoechea JR, Pety J, Le Gal R, Martín-Doménech R, Gratier P, Guzmán V, Roueff E, Loison JC, Muñoz Caro GM, Wakelam V, Gerin M, Riviere-Marichalar P, Vidal T. First Detection of Interstellar S 2H. Astrophys J Lett 2017; 851:L49. [PMID: 29862006 PMCID: PMC5975949 DOI: 10.3847/2041-8213/aaa01b] [Citation(s) in RCA: 47] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
We present the first detection of gas phase S2H in the Horsehead, a moderately UV-irradiated nebula. This confirms the presence of doubly sulfuretted species in the interstellar medium and opens a new challenge for sulfur chemistry. The observed S2H abundance is ~5×10-11, only a factor 4-6 lower than that of the widespread H2S molecule. H2S and S2H are efficiently formed on the UV-irradiated icy grain mantles. We performed ice irradiation experiments to determine the H2S and S2H photodesorption yields. The obtained values are ~1.2×10-3 and <1×10-5 molecules per incident photon for H2S and S2H, respectively. Our upper limit to the S2H photodesorption yield suggests that photo-desorption is not a competitive mechanism to release the S2H molecules to the gas phase. Other desorption mechanisms such as chemical desorption, cosmic-ray desorption and grain shattering can increase the gaseous S2H abundance to some extent. Alternatively, S2H can be formed via gas phase reactions involving gaseous H2S and the abundant ions S+ and SH+. The detection of S2H in this nebula could be therefore the result of the coexistence of an active grain surface chemistry and gaseous photo-chemistry.
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Affiliation(s)
- Asunción Fuente
- Observatorio Astronómico Nacional (OAN,IGN), Apdo 112, E-28803 Alcalá de Henares, Spain
| | - Javier R. Goicoechea
- Instituto de Ciencia de Materiales de Madrid (ICMM-CSIC), Sor Juana Ins de la Cruz, 3, E-28049 Cantoblanco, Madrid, Spain
| | - Jerome Pety
- Institut de Radioastronomie Millimétrique (IRAM), 300 rue de la Piscine, 38406 Saint Martin d’Hères, France
- LERMA, Observatoire de Paris, PSL Research University, CNRS, Sorbonne Universités, UPMC Univ. Paris 06, Ecole Normale Supérieure, F-75005 Paris, France
| | - Romane Le Gal
- Harvard-Smithsonian Center for Astrophysics, 60 Garden St., Cambridge, MA 02138, USA
| | | | - Pierre Gratier
- Laboratoire d’Astrophysique de Bordeaux, Univ. Bordeaux, CNRS, B18N, allée Geoffroy Saint-Hilaire, 33615 Pessac, France
| | - Viviana Guzmán
- Joint ALMA Observatory (JAO), Alonso de Córdova 3107, Vitacura, Santiago, Chile
| | - Evelyne Roueff
- LERMA, Observatoire de Paris, PSL Research University, CNRS, Sorbonne Universités, UPMC Univ. Paris 06, F-92190 Meudon, France
| | - Jean Christophe Loison
- Institut des Sciences Moléculaires de Bordeaux (ISM), CNRS, Univ. Bordeaux, 351 cours de la Libération, 33400, Talence, France
| | - Guillermo M. Muñoz Caro
- Centro de Astrobiología (CSIC-INTA), Carretera de Ajalvir, km 4, Torrejón de Ardoz, 28850 Madrid, Spain
| | - Valentine Wakelam
- Laboratoire d’Astrophysique de Bordeaux, Univ. Bordeaux, CNRS, B18N, allée Geoffroy Saint-Hilaire, 33615 Pessac, France
| | - Maryvonne Gerin
- LERMA, Observatoire de Paris, PSL Research University, CNRS, Sorbonne Universités, UPMC Univ. Paris 06, Ecole Normale Supérieure, F-75005 Paris, France
| | - Pablo Riviere-Marichalar
- Instituto de Ciencia de Materiales de Madrid (ICMM-CSIC), Sor Juana Ins de la Cruz, 3, E-28049 Cantoblanco, Madrid, Spain
| | - Thomas Vidal
- Laboratoire d’Astrophysique de Bordeaux, Univ. Bordeaux, CNRS, B18N, allée Geoffroy Saint-Hilaire, 33615 Pessac, France
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48
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de Barros ALF, Mattioda AL, Ricca A, Cruz G, Allamandola LJ. Photochemistry of coronene in cosmic water ice analogs at different concentrations. Astrophys J 2017; 848:112. [PMID: 29151610 PMCID: PMC5688519 DOI: 10.3847/1538-4357/aa8c71] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
This work presents the photochemistry of ultraviolet (UV) irradiated coronene in water ices at 15 K, studied using mid-infrared Fourier transform (FTIR) spectroscopy for C24H12:H2O at concentrations of (1:50), (1:150), (1:200), (1:300) and (1:400). Previous UV irradiation studies of anthracene:H2O, pyrene:H2O and benzo[ghi]perylene:H2O ices at 15 K have shown that aromatic alcohols and ketones, as well as CO2 and H2CO are formed at very low temperatures. Like-wise, here, in addition to the coronene cation, hydroxy-, keto-, and protonated coronene (coronene-H+) are formed. The rate constants for the decay of neutral coronene and for the formation of photoproducts have been derived. It is shown that PAHs and their UV-induced PAH:H2O photoproducts have mid-infrared spectroscopic signatures in the 5-8 μm region that can contribute to the interstellar ice components described by Boogert et al. (2008) as C1-C5. Our results suggest that oxygenated and hydrogenated PAHs could be in UV-irradiated regions of the ISM where water-rich ices are important.
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Affiliation(s)
- A L F de Barros
- Departamento de Física, Centro Federal de Educação Tecnológica Celso Suckow da Fonseca, Av. Maracanã 229, 20271-110 Rio de Janeiro, RJ, Brazil
| | - A L Mattioda
- NASA Ames Research Center, Mail Stop 245-6, Moffett Field, CA 94035-1000, USA
| | - A Ricca
- Carl Sagan Center, SETI Institute, 189 Bernardo Ave., Mountain View, CA 94043, USA
| | - G Cruz
- Bay Area Environmental Institute, 625 2nd St., Suite 209, Petaluma, CA, 94952, USA
| | - L J Allamandola
- NASA Ames Research Center, Mail Stop 245-6, Moffett Field, CA 94035-1000, USA
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Cox NLJ, Cami J, Farhang A, Smoker J, Monreal-Ibero A, Lallement R, Sarre PJ, Marshall CCM, Smith KT, Evans CJ, Royer P, Linnartz H, Cordiner MA, Joblin C, van Loon JT, Foing BH, Bhatt NH, Bron E, Elyajouri M, de Koter A, Ehrenfreund P, Javadi A, Kaper L, Khosroshadi HG, Laverick M, Le Petit F, Mulas G, Roueff E, Salama F, Spaans M. The ESO Diffuse Interstellar Bands Large Exploration Survey: EDIBLES I. Project description, survey sample and quality assessment. Astron Astrophys 2017; 606:A76. [PMID: 29151608 PMCID: PMC5693340 DOI: 10.1051/0004-6361/201730912] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
The carriers of the diffuse interstellar bands (DIBs) are largely unidentified molecules ubiquitously present in the interstellar medium (ISM). After decades of study, two strong and possibly three weak near-infrared DIBs have recently been attributed to the [Formula: see text] fullerene based on observational and laboratory measurements. There is great promise for the identification of the over 400 other known DIBs, as this result could provide chemical hints towards other possible carriers. In an effort to systematically study the properties of the DIB carriers, we have initiated a new large-scale observational survey: the ESO Diffuse Interstellar Bands Large Exploration Survey (EDIBLES). The main objective is to build on and extend existing DIB surveys to make a major step forward in characterising the physical and chemical conditions for a statistically significant sample of interstellar lines-of-sight, with the goal to reverse-engineer key molecular properties of the DIB carriers. EDIBLES is a filler Large Programme using the Ultraviolet and Visual Echelle Spectrograph at the Very Large Telescope at Paranal, Chile. It is designed to provide an observationally unbiased view of the presence and behaviour of the DIBs towards early-spectral type stars whose lines-of-sight probe the diffuse-to-translucent ISM. Such a complete dataset will provide a deep census of the atomic and molecular content, physical conditions, chemical abundances and elemental depletion levels for each sightline. Achieving these goals requires a homogeneous set of high-quality data in terms of resolution (R ~ 70 000 - 100 000), sensitivity (S/N up to 1000 per resolution element), and spectral coverage (305-1042 nm), as well as a large sample size (100+ sightlines). In this first paper the goals, objectives and methodology of the EDIBLES programme are described and an initial assessment of the data is provided.
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Affiliation(s)
- Nick L J Cox
- Université de Toulouse, UPS-OMP, IRAP, 31028, Toulouse, France
- CNRS, IRAP, 9 Av. colonel Roche, BP 44346, F-31028 Toulouse, France
| | - Jan Cami
- Department of Physics and Astronomy, The University of Western Ontario, London, ON N6A 3K7, Canada
- SETI Institute, 189 Bernardo Avenue, Suite 100, Mountain View, CA 94043, USA
| | - Amin Farhang
- School of Astronomy, Institute for Research in Fundamental Sciences, 19395-5531 Tehran, Iran
| | - Jonathan Smoker
- European Southern Observatory, Alonso de Cordova 3107, Vitacura, Santiago, Chile
| | - Ana Monreal-Ibero
- GEPI, Observatoire de Paris, PSL Research University, CNRS, Université Paris-Diderot, Sorbonne Paris Cité, Place Jules Janssen, 92195 Meudon, France
- Instituto de Astrofísica de Canarias (IAC), E-38205 La Laguna, Tenerife, Spain
- Universidad de La Laguna, Dpto. Astrofísica, E-38206 La Laguna, Tenerife, Spain
| | - Rosine Lallement
- GEPI, Observatoire de Paris, PSL Research University, CNRS, Université Paris-Diderot, Sorbonne Paris Cité, Place Jules Janssen, 92195 Meudon, France
| | - Peter J Sarre
- School of Chemistry, The University of Nottingham, University Park, Nottingham NG7 2RD, UK
| | - Charlotte C M Marshall
- School of Chemistry, The University of Nottingham, University Park, Nottingham NG7 2RD, UK
| | - Keith T Smith
- Royal Astronomical Society, Burlington House, Piccadilly, London W1J 0BQ, UK
- AAAS Science International, Clarendon House, Clarendon Road, Cambridge CB2 8FH, UK
| | - Christopher J Evans
- UK Astronomy Technology Centre, Royal Observatory, Blackford Hill, Edinburgh, EH9 3HJ, UK
| | - Pierre Royer
- Instituut voor Sterrenkunde, KULeuven, Celestijnenlaan 200D, bus 2401, Leuven, Belgium
| | - Harold Linnartz
- Sackler Laboratory for Astrophysics, Leiden Observatory, Leiden University, PO Box 9513, NL2300 RA Leiden, The Netherlands
| | - Martin A Cordiner
- Astrochemistry Laboratory, NASA Goddard Space Flight Center, Code 691, 8800 Greenbelt Road, Greenbelt, MD 20771, USA
- Department of Physics, The Catholic University of America, Washington, DC 20064, USA
| | - Christine Joblin
- Université de Toulouse, UPS-OMP, IRAP, 31028, Toulouse, France
- CNRS, IRAP, 9 Av. colonel Roche, BP 44346, F-31028 Toulouse, France
| | | | | | - Neil H Bhatt
- Department of Physics and Astronomy, The University of Western Ontario, London, ON N6A 3K7, Canada
| | | | - Meriem Elyajouri
- GEPI, Observatoire de Paris, PSL Research University, CNRS, Université Paris-Diderot, Sorbonne Paris Cité, Place Jules Janssen, 92195 Meudon, France
| | - Alex de Koter
- Anton Pannekoek Institute for Astronomy, University of Amsterdam, NL-1090 GE Amsterdam, The Netherlands
- Instituut voor Sterrenkunde, KULeuven, Celestijnenlaan 200D, bus 2401, Leuven, Belgium
| | | | - Atefeh Javadi
- School of Astronomy, Institute for Research in Fundamental Sciences, 19395-5531 Tehran, Iran
| | - Lex Kaper
- Anton Pannekoek Institute for Astronomy, University of Amsterdam, NL-1090 GE Amsterdam, The Netherlands
| | - Habib G Khosroshadi
- School of Astronomy, Institute for Research in Fundamental Sciences, 19395-5531 Tehran, Iran
| | - Mike Laverick
- Instituut voor Sterrenkunde, KULeuven, Celestijnenlaan 200D, bus 2401, Leuven, Belgium
| | - Franck Le Petit
- LERMA, Observatoire de Paris, PSL Research University, CNRS, Sorbonne Universités, UPMC Université Paris 06, 92190 Meudon, France
| | - Giacomo Mulas
- INAF - Osservatorio Astronomico di Cagliari, Via della Scienza 5, I-09047 Selargius, Italy
| | - Evelyne Roueff
- LERMA, Observatoire de Paris, PSL Research University, CNRS, Sorbonne Universités, UPMC Université Paris 06, 92190 Meudon, France
| | - Farid Salama
- NASA Ames Research Center, Space Science & Astrobiology Division, Moffett Field, California, USA
| | - Marco Spaans
- Kapteyn Institute, University of Groningen, Groningen, The Netherlands
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50
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Loison JC, Agúndez M, Wakelam V, Roueff E, Gratier P, Marcelino N, Nuñez Reyes D, Cernicharo J, Gerin M. The interstellar chemistry of C 3H and C 3H 2 isomers. Mon Not R Astron Soc 2017; 470:4075-4088. [PMID: 29142332 PMCID: PMC5683352 DOI: 10.1093/mnras/stx1265] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
We report the detection of linear and cyclic isomers of C3H and C3H2 towards various starless cores and review the corresponding chemical pathways involving neutral (C3Hx with x=1,2) and ionic (C3Hx+ with x = 1,2,3) isomers. We highlight the role of the branching ratio of electronic Dissociative Recombination (DR) reactions of C3H2+ and C3H3+ isomers showing that the statistical treatment of the relaxation of C3H* and C3H2* produced in these DR reactions may explain the relative c,l-C3H and c,l-C3H2 abundances. We have also introduced in the model the third isomer of C3H2 (HCCCH). The observed cyclic-to-linear C3H2 ratio vary from 110 ± 30 for molecular clouds with a total density around 1×104 molecules.cm-3 to 30 ± 10 for molecular clouds with a total density around 4×105 molecules.cm-3, a trend well reproduced with our updated model. The higher ratio for low molecular cloud densities is mainly determined by the importance of the H + l-C3H2 → H + c-C3H2 and H + t-C3H2 → H + c-C3H2 isomerization reactions.
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Affiliation(s)
- Jean-Christophe Loison
- Institut des Sciences Moléculaires (ISM), CNRS, Univ. Bordeaux, 351 cours de la Libération, 33400, Talence, France
| | - Marcelino Agúndez
- Instituto de Ciencia de Materiales de Madrid, CSIC, C\ Sor Juana Inés de la Cruz 3, 28049 Cantoblanco, Spain
| | - Valentine Wakelam
- Laboratoire d'astrophysique de Bordeaux, Univ. Bordeaux, CNRS, B18N, allée Geoffroy Saint-Hilaire, 33615 Pessac, France
| | - Evelyne Roueff
- LERMA, Observatoire de Paris, PSL Research University, CNRS, Sorbonne Universités, UPMC Univ. Paris 06, F-92190 Meudon, France
| | - Pierre Gratier
- Laboratoire d'astrophysique de Bordeaux, Univ. Bordeaux, CNRS, B18N, allée Geoffroy Saint-Hilaire, 33615 Pessac, France
| | - Núria Marcelino
- INAF, Osservatorio di Radioastronomia, via P. Gobetti 101, 40129 Bologna, Italy
| | - Dianailys Nuñez Reyes
- Institut des Sciences Moléculaires (ISM), CNRS, Univ. Bordeaux, 351 cours de la Libération, 33400, Talence, France
| | - José Cernicharo
- Instituto de Ciencia de Materiales de Madrid, CSIC, C\ Sor Juana Inés de la Cruz 3, 28049 Cantoblanco, Spain
| | - Maryvonne Gerin
- LERMA, Observatoire de Paris, PSL Research University, CNRS, Sorbonne Universités, UPMC Univ. Paris 06, Ecole Normale Supérieure, F-75005 Paris, France
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