1
|
Todd ZR. Sources of Nitrogen-, Sulfur-, and Phosphorus-Containing Feedstocks for Prebiotic Chemistry in the Planetary Environment. Life (Basel) 2022; 12:1268. [PMID: 36013447 PMCID: PMC9410288 DOI: 10.3390/life12081268] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2022] [Revised: 08/13/2022] [Accepted: 08/17/2022] [Indexed: 11/21/2022] Open
Abstract
Biochemistry on Earth makes use of the key elements carbon, hydrogen, oxygen, nitrogen, phosphorus, and sulfur (or CHONPS). Chemically accessible molecules containing these key elements would presumably have been necessary for prebiotic chemistry and the origins of life on Earth. For example, feedstock molecules including fixed nitrogen (e.g., ammonia, nitrite, nitrate), accessible forms of phosphorus (e.g., phosphate, phosphite, etc.), and sources of sulfur (e.g., sulfide, sulfite) may have been necessary for the origins of life, given the biochemistry seen in Earth life today. This review describes potential sources of nitrogen-, sulfur-, and phosphorus-containing molecules in the context of planetary environments. For the early Earth, such considerations may be able to aid in the understanding of our own origins. Additionally, as we learn more about potential environments on other planets (for example, with upcoming next-generation telescope observations or new missions to explore other bodies in our Solar System), evaluating potential sources for elements necessary for life (as we know it) can help constrain the potential habitability of these worlds.
Collapse
Affiliation(s)
- Zoe R Todd
- Department of Earth and Space Sciences, University of Washington, Seattle, WA 98195, USA
| |
Collapse
|
2
|
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 . ASTRONOMY AND ASTROPHYSICS 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] [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.
Collapse
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
| |
Collapse
|
3
|
Pardo JR, Bermúdez C, Cabezas C, Agúndez M, Gallego JD, Fonfría JP, Velilla-Prieto L, Quintana-Lacaci G, Tercero B, Guélin M, Cernicharo J. Detection of vibrationally excited HC 7N and HC 9N in IRC+10216 ⋆. ASTRONOMY AND ASTROPHYSICS 2020; 640:L13. [PMID: 33173233 PMCID: PMC7116341 DOI: 10.1051/0004-6361/202038571] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
Observations of IRC +10216 with the Yebes 40m telescope between 31 and 50 GHz have revealed more than 150 unidentified lines. Some of them can be grouped into a new series of 26 doublets, harmonically related with integer quantum numbers ranging from J up=54 to 80. The separation of the doublets increases systematically with J, i.e., as expected for a linear species in one of its bending modes. The rotational parameters resulting from the fit to these data are B = 290.8844 ± 0.0004 MHz, D = 0.88 ± 0.04 Hz, q = 0.1463 ± 0.0001 MHz. The rotational constant is very close to that of the ground state of HC9N. Ab initio calculations show an excellent agreement between these parameters and those predicted for the lowest energy vibrationally excited state, ν 19=1, of HC9N. This is the first detection, and complete characterization in space, of vibrationally excited HC9N. An energy of 41.5 cm-1 is estimated for the ν 19 state. In addition, 17 doublets of HC7N in the ν 15=1 state, for which laboratory spectroscopy is available, have been detected for the first time in IRC+10216. Several doublets of HC5N in its ν 11=1 state have been also observed. The column density ratio between the ground and the lowest excited vibrational states are ≈127, 9.5, and 1.5 for HC5N, HC7N, and HC9N, respectively. We find that these lowest-lying vibrational states are most probably populated via infrared pumping to vibrationally excited states lying at ≈600 cm-1. The lowest vibrationally excited states thus need to be taken into account to precisely determine absolute abundances and abundanceratios for long carbon chains. The abundance ratios N(HC5N)/N(HC7N) and N(HC7N)/N(HC9N) are 2.4 and 7.7 respectively.
Collapse
Affiliation(s)
- J. R. Pardo
- 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
| | - M. Agúndez
- 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
| | - J. P. Fonfría
- Grupo de Astrofísica Molecular, Instituto de Física Fundamental (IFF-CSIC), C/ Serrano 121, 28006 Madrid, Spain
| | - L. Velilla-Prieto
- Grupo de Astrofísica Molecular, Instituto de Física Fundamental (IFF-CSIC), C/ Serrano 121, 28006 Madrid, Spain
- Dept. of Space, Earth and Environment, Chalmers University of Technology, Onsala Space Observatory, 439 92 Onsala, Sweden
| | - G. Quintana-Lacaci
- 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
| | - M. Guélin
- Institut de Radioastronomie Millimétrique, 300 rue de la Piscine, F-38406, Saint Martin d’Hères, France
| | - J. Cernicharo
- Grupo de Astrofísica Molecular, Instituto de Física Fundamental (IFF-CSIC), C/ Serrano 121, 28006 Madrid, Spain
| |
Collapse
|
4
|
Cernicharo J, Cabezas C, Pardo JR, Agúndez M, Bermúdez C, Velilla-Prieto L, Tercero F, López-Pérez JA, Gallego JD, Fonfría JP, Quintana-Lacaci G, Guélin M, Endo Y. Discovery of two new magnesium-bearing species in IRC+10216: MgC 3N and MgC 4H. ASTRONOMY AND ASTROPHYSICS 2019; 630:L2. [PMID: 31579315 PMCID: PMC6774763 DOI: 10.1051/0004-6361/201936372] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
Abstract
We report on the detection of two series of harmonically related doublets in IRC +10216. From the observed frequencies, the rotational constant of the first series is B = 1380.888 MHz and that of the second series is B = 1381.512 MHz. The two series correspond to two species with a 2Σ electronic ground state. After considering all possible candidates, and based on quantum chemical calculations, the first series is assigned to MgC3N and the second to MgC4H. For the latter species, optical spectroscopy measurements support its identification. Unlike diatomic metal-containing molecules, the line profiles of the two new molecules indicate that they are formed in the outer layers of the envelope, as occurs for MgNC and other polyatomic metal-cyanides. We also confirm the detection of MgCCH that was previously reported from the observation of two doublets. The relative abundance of MgC3N with respect to MgNC is close to one while that of MgC4H relative to MgCCH is about ten. The synthesis of these magnesium cyanides and acetylides in IRC +10216 can be explained in terms of a two-step process initiated by the radiative association of Mg+ with large cyanopolyynes and polyynes followed by the dissociative recombination of the ionic complexes.
Collapse
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
| | - 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
| | - C. Bermúdez
- Grupo de Astrofísica Molecular. Instituto de Física Fundamental (IFF-CSIC). C/Serrano 121, 28006 Madrid, Spain
| | - L. Velilla-Prieto
- Grupo de Astrofísica Molecular. Instituto de Física Fundamental (IFF-CSIC). C/Serrano 121, 28006 Madrid, Spain
- Department of Space, Earth and Environment, Chalmers University of Technology, Onsala Space Observatory, 439 92 Onsala, Sweden
| | - 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
| | - J. P. Fonfría
- Grupo de Astrofísica Molecular. Instituto de Física Fundamental (IFF-CSIC). C/Serrano 121, 28006 Madrid, Spain
| | - G. Quintana-Lacaci
- Grupo de Astrofísica Molecular. Instituto de Física Fundamental (IFF-CSIC). C/Serrano 121, 28006 Madrid, Spain
| | - M. Guélin
- Institut de Radioastronomie Millimétrique, 300 rue de la Piscine, F-38406, Saint Martin d’Hères, France
| | - Y. Endo
- Department of Applied Chemistry, Science Building II, National Chiao Tung University, 1001 Ta-Hsueh Rd., Hsinchu 30010, Taiwan
| |
Collapse
|
5
|
Cernicharo J, Velilla-Prieto L, Agúndez M, Pardo J, Fonfría J, Quintana-Lacaci G, Cabezas C, Bermúdez C, Guélin M. Discovery of the first Ca-bearing molecule in space: CaNC. ASTRONOMY AND ASTROPHYSICS 2019; 627:L4. [PMID: 31327871 PMCID: PMC6640036 DOI: 10.1051/0004-6361/201936040] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
We report on the detection of calcium isocyanide, CaNC, in the carbon-rich evolved star IRC+10216. We derived a column density for this species of (2±0.5)×1011 cm-2. Based on the observed line profiles and the modelling of its emission through the envelope, the molecule has to be produced in the intermediate and outer layers of the circumstellar envelope where other metal-isocyanides have previously been found in this source. The abundance ratio of CaNC relative to MgNC and FeCN is ≃1/60 and ≃1, respectively. We searched for the species CaF, CaCl, CaC, CaCCH, and CaCH3 for which accurate frequency predictions are available. Only upper limits have been obtained for these molecules.
Collapse
Affiliation(s)
- J. Cernicharo
- Grupo de Astrofísica Molecular. Instituto de Física Fundamental (IFF-CSIC). C/Serrano 121, 28006 Madrid, Spain
| | - L. Velilla-Prieto
- Grupo de Astrofísica Molecular. Instituto de Física Fundamental (IFF-CSIC). C/Serrano 121, 28006 Madrid, Spain
- Department of Space, Earth and Environment, Chalmers University of Technology, Onsala Space Observatory, 439 92 Onsala, Sweden
| | - M. Agúndez
- 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
| | - J.P. Fonfría
- Grupo de Astrofísica Molecular. Instituto de Física Fundamental (IFF-CSIC). C/Serrano 121, 28006 Madrid, Spain
| | - G. Quintana-Lacaci
- 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
| | - C. Bermúdez
- Grupo de Astrofísica Molecular. Instituto de Física Fundamental (IFF-CSIC). C/Serrano 121, 28006 Madrid, Spain
| | - M. Guélin
- Institut de Radioastronomie Millimétrique, 300 rue de la Piscine, F-38406, Saint Martin d’Hères, France
| |
Collapse
|
6
|
Sánchez Contreras C, Alcolea J, Bujarrabal V, Castro-Carrizo A, Prieto LV, Santander-García M, Quintana-Lacaci G, Cernicharo J. Through the magnifying glass: ALMA acute viewing of the intricate nebular architecture of OH231.8+4.2. ASTRONOMY AND ASTROPHYSICS 2018; 618:A164. [PMID: 30473586 PMCID: PMC6251484 DOI: 10.1051/0004-6361/201833632] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
We present continuum and molecular line emission ALMA observations of OH 231.8+4.2, a well studied bipolar nebula around an asymptotic giant branch (AGB) star. The high angular resolution ( ∼ 0 · ″ 2 - 0 · ″ 3 ) and sensitivity of our ALMA maps provide the most detailed and accurate description of the overall nebular structure and kinematics of this object to date. We have identified a number of outflow components previously unknown. Species studied in this work include 12CO, 13CO, CS, SO, SO2, QCS, SiO, SiS, H3O+, Na37Cl, and CH3OH. The molecules Na37Cl and CH3OH are first detections in OH 231.8+4.2, with CH3OH being also a first detection in an AGB star. Our ALMA maps bring to light the totally unexpected position of the mass-losing AGB star (QX Pup) relative to the large-scale outflow. QX Pup is enshrouded within a compact (≲60 AU) parcel of dust and gas (clump S) in expansion (V exp~5-7 km s-1) that is displaced by ∼ 0 · ″ 6 to the south of the dense equatorial region (or waist) where the bipolar lobes join. Our SiO maps disclose a compact bipolar outflow that emerges from QX Pup's vicinity. This outflow is oriented similarly to the large-scale nebula but the expansion velocities are about ten times lower (V exp≲35km s-1). We deduce short kinematical ages for the SiO outflow, ranging from ~50-80 yr, in regions within ~150 AU, to ~400-500 yr at the lobe tips (~3500 AU). Adjacent to the SiO outflow, we identify a small-scale hourglass-shaped structure (mini-hourglass) that is probably made of compressed ambient material formed as the SiO outflow penetrates the dense, central regions of the nebula. The lobes and the equatorial waist of the mini-hourglass are both radially expanding with a constant velocity gradient (V exp ∝ r). The mini-waist is characterized by extremely low velocities, down to ~1 km s-1 at ~150 AU, which tentatively suggest the presence of a stable structure. The spatio-kinematics of the large-scale, high-velocity lobes (HV lobes) and the dense equatorial waist (large waist) known from previous works are now precisely determined, indicating that both were shaped nearly simultaneously about ~800-900 yr ago. We report the discovery of two large (~8″×6″), faint bubble-like structures (fish bowls) surrounding the central parts of the nebula. These are relatively old structures although probably slightly (~100-200 yr) younger than the large waist and the HV lobes. We discuss the series of events that may have resulted in the complex array of nebular components found in OH 231.8+4.2 as well as the properties and locus of the central binary system. The presence of ≲80 yr bipolar ejections indicate that the collimated fast wind engine is still active at the core of this outstanding object.
Collapse
Affiliation(s)
- C Sánchez Contreras
- Centro de Astrobiología (CSIC-INTA), Postal address: ESAC, Camino Bajo del Castillo s/n, Urb. Villafranca del Castillo, E-28691 Villanueva de la Cañada, Madrid, Spain
| | - J Alcolea
- Observatorio Astronómico Nacional (IGN), Alfonso XII No 3, 28014 Madrid, Spain
| | - V Bujarrabal
- Observatorio Astronómico Nacional (IGN), Ap 112, 28803 Alcalá de Henares, Madrid, Spain
| | - A Castro-Carrizo
- Institut de Radioastronomie Millimetrique, 300 rue de la Piscine, 38406 Saint Martin d'Heres, France
| | - L Velilla Prieto
- Instituto de Fisica Fundamental (CSIC), C/ Serrano, 123, E-28006, Madrid, Spain
| | - M Santander-García
- Observatorio Astronómico Nacional (IGN), Alfonso XII No 3, 28014 Madrid, Spain
| | - G Quintana-Lacaci
- Instituto de Fisica Fundamental (CSIC), C/ Serrano, 123, E-28006, Madrid, Spain
| | - J Cernicharo
- Instituto de Fisica Fundamental (CSIC), C/ Serrano, 123, E-28006, Madrid, Spain
| |
Collapse
|
7
|
Cernicharo J, Guélin M, Agúndez M, Pardo JR, Massalkhi S, Fonfría JP, Velilla Prieto L, Quintana-Lacaci G, Marcelino N, Marka C, Navarro S, Kramer C. IRC +10216 as a spectroscopic laboratory: improved rotational constants for SiC 2, its isotopologues, and Si 2C. ASTRONOMY AND ASTROPHYSICS 2018; 618:A4. [PMID: 30429616 PMCID: PMC6231541 DOI: 10.1051/0004-6361/201833335] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
This work presents a detailed analysis of the laboratory and astrophysical spectral data available for 28SiC2, 29SiC2,30SiC2, Si13CC, and Si2C. New data on the rotational lines of these species between 70 and 350 GHz have been obtained with high spectral resolution (195 kHz) with the IRAM 30m telescope in the direction of the circumstellar envelope IRC +10216. Frequency measurements can reach an accuracy of 50 kHz for features observed with a good signal to noise ratio. From the observed astrophysical lines and the available laboratory data new rotational and centrifugal distortion constants have been derived for all the isotopologues of SiC2, allowing to predict their spectrum with high accuracy in the millimeter and submillimeter domains. Improved rotational and centrifugal distortion constants have also been obtained for disilicon carbide, Si2C. This work shows that observations of IRC +10216 taken with the IRAM 30m telescope, with a spectral resolution of 195 kHz, can be used for any molecular species detected in this source to derive, or improve, its rotational constants. Hence, IRC +10216 in addition to be one the richest sources in molecular species in the sky, can also be used as a state-of-the-art spectroscopy laboratory in the millimeter and submillimeter domains.
Collapse
Affiliation(s)
- J. Cernicharo
- Group of Molecular Astrophysics, Instituto de Física Fundamental, CSIC, C/ Serrano 123, E-28006, Madrid, Spain
| | - M. Guélin
- Institut de Radioastronomie Millimétrique, 300 rue de la Piscine, F-38406, Saint Martin d'Hères, France
| | - M. Agúndez
- Group of Molecular Astrophysics, Instituto de Física Fundamental, CSIC, C/ Serrano 123, E-28006, Madrid, Spain
| | - J. R. Pardo
- Group of Molecular Astrophysics, Instituto de Física Fundamental, CSIC, C/ Serrano 123, E-28006, Madrid, Spain
| | - S. Massalkhi
- Group of Molecular Astrophysics, Instituto de Física Fundamental, CSIC, C/ Serrano 123, E-28006, Madrid, Spain
| | - J. P. Fonfría
- Group of Molecular Astrophysics, Instituto de Física Fundamental, CSIC, C/ Serrano 123, E-28006, Madrid, Spain
| | - L. Velilla Prieto
- Group of Molecular Astrophysics, Instituto de Física Fundamental, CSIC, C/ Serrano 123, E-28006, Madrid, Spain
| | - G. Quintana-Lacaci
- Group of Molecular Astrophysics, Instituto de Física Fundamental, CSIC, C/ Serrano 123, E-28006, Madrid, Spain
| | - N. Marcelino
- Group of Molecular Astrophysics, Instituto de Física Fundamental, CSIC, C/ Serrano 123, E-28006, Madrid, Spain
| | - C. Marka
- Instituto de Radioastronomía Milimétrica, Avenida Divina Pastora 7, E-18012, Granada, Spain
| | - S. Navarro
- Instituto de Radioastronomía Milimétrica, Avenida Divina Pastora 7, E-18012, Granada, Spain
| | - C. Kramer
- Instituto de Radioastronomía Milimétrica, Avenida Divina Pastora 7, E-18012, Granada, Spain
| |
Collapse
|
8
|
Pardo JR, Cernicharo J, Velilla Prieto L, Fonfría JP, Agúndez M, Quintana-Lacaci G, Massalkhi S, Tercero B, Gómez-Garrido M, de Vicente P, Guélin M, Kramer C, Marka C, Teyssier D, Neufeld D. Time-dependent molecular emission in IRC+10216. ASTRONOMY AND ASTROPHYSICS 2018; 615:L4. [PMID: 30185989 PMCID: PMC6120678 DOI: 10.1051/0004-6361/201833303] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
CONTEXT The variability in IRC+10216, the envelope of the asymptotic giant branch (AGB) star CW Leo, has attracted increasing attention in recent years. Studying the details of this variability in the molecular emission required a systematic observation program. AIMS We aim to reveal and characterize the periodical variability of the rotational lines from several molecules and radicals in IRC+10216, and to compare it with previously reported IR variability. METHODS We carried out systematic monitoring within the ~80 to 116 GHz frequency range with the IRAM 30m telescope. RESULTS We report on the periodical variability in IRC+10216 of several rotational lines from the following molecules and radicals: HC3N, HC5N, CCH, C4H, C5H, and CN. The analysis of the variable molecular lines provides periods that are consistent with previously reported IR variability, and interesting phase lags are revealed that point toward radiative transfer and pumping, rather than chemical effects. CONCLUSIONS This study indicates that observations of several lines of a given molecule have to be performed simultaneously or at least at the same phase in order to avoid erroneous interpretation of the data. In particular, merging ALMA data from different epochs may prove to be difficult, as shown by the example of the variability we studied here. Moreover, radiative transfer codes have to incorporate the effect of population variability in the rotational levels in CW Leo.
Collapse
Affiliation(s)
- J R Pardo
- Consejo Superior de Investigaciones Científicas, Instituto de Física Fundamental, Serrano 123, 28006 Madrid, Spain
| | - J Cernicharo
- Consejo Superior de Investigaciones Científicas, Instituto de Física Fundamental, Serrano 123, 28006 Madrid, Spain
| | - L Velilla Prieto
- Consejo Superior de Investigaciones Científicas, Instituto de Física Fundamental, Serrano 123, 28006 Madrid, Spain
| | - J P Fonfría
- Consejo Superior de Investigaciones Científicas, Instituto de Física Fundamental, Serrano 123, 28006 Madrid, Spain
| | - M Agúndez
- Consejo Superior de Investigaciones Científicas, Instituto de Física Fundamental, Serrano 123, 28006 Madrid, Spain
| | - G Quintana-Lacaci
- Consejo Superior de Investigaciones Científicas, Instituto de Física Fundamental, Serrano 123, 28006 Madrid, Spain
| | - S Massalkhi
- Consejo Superior de Investigaciones Científicas, Instituto de Física Fundamental, Serrano 123, 28006 Madrid, Spain
| | - B Tercero
- Instituto Geográfico Nacional, Centro de Desarrollos Tecnológicos, Observatorio de Yebes, Apartado 148, 19080 Yebes, Spain
| | - M Gómez-Garrido
- Instituto Geográfico Nacional, Centro de Desarrollos Tecnológicos, Observatorio de Yebes, Apartado 148, 19080 Yebes, Spain
| | - P de Vicente
- Instituto Geográfico Nacional, Centro de Desarrollos Tecnológicos, Observatorio de Yebes, Apartado 148, 19080 Yebes, Spain
| | - M Guélin
- Institut de Radioastronomie Millimétrique, 300 rue de la Piscine, 38406 St-Martin d'Hères, France
| | - C Kramer
- Instituto de Radioastronomía Milimétrica, Av. Divina Pastora 7, Local 20, 18012 Granada, Spain
| | - C Marka
- Instituto de Radioastronomía Milimétrica, Av. Divina Pastora 7, Local 20, 18012 Granada, Spain
| | - D Teyssier
- Herschel Science Centre, ESA/ESAC, P.O. Box 78, Villanueva de la Cañada, Madrid, Spain
| | - D Neufeld
- Department of Physics and Astronomy, John Hopkins University, 3400 North Charles Street, Baltimore, MD 21218, USA
| |
Collapse
|
9
|
Fonfría JP, Fernández-López M, Pardo JR, Agúndez M, Sánchez Contreras C, Velilla Prieto L, Cernicharo J, Santander-García M, Quintana-Lacaci G, Castro-Carrizo A, Curiel S. The Maser Emitting Structure and Time Variability of the SIS Lines J = 14 - 13 and 15 - 14 in IRC+10216. THE ASTROPHYSICAL JOURNAL 2018; 860:162. [PMID: 29977091 PMCID: PMC6029660 DOI: 10.3847/1538-4357/aac5e3] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
We present new high angular resolution interferometer observations of the υ = 0 J = 14 - 13 and 15 - 14 SiS lines towards IRC+10216, carried out with CARMA and ALMA. The maps, with angular resolutions of ≃ 0 ⋅ ″ 25 and 0 ⋅ ″ 55 , reveal (1) an extended, roughly uniform, and weak emission with a size of ≃ 0 ⋅ ″ 5 , (2) a component elongated approximately along the East-West direction peaking at ≃ 0 ⋅ ″ 13 and 0 ⋅ ″ 17 at both sides of the central star, and (3) two blue- and red-shifted compact components peaking around 0 ⋅ ″ 07 to the NW of the star. We have modeled the emission with a 3D radiation transfer code finding that the observations cannot be explained only by thermal emission. Several maser clumps and one arc-shaped maser feature arranged from 5 to 20R⋆ from the central star, in addition to a thin shell-like maser structure at ≃ 13R⋆ are required to explain the observations. This maser emitting set of structures accounts for 75% of the total emission while the other 25% is produced by thermally excited molecules. About 60% of the maser emission comes from the extended emission and the rest from the set of clumps and the arc. The analysis of a time monitoring of these and other SiS and 29SiS lines carried out with the IRAM 30 m telescope from 2015 to present suggests that the intensity of some spectral components of the maser emission strongly depends on the stellar pulsation while other components show a mild variability. This monitoring evidences a significant phase lag of ≃ 0.2 between the maser and NIR light-curves.
Collapse
Affiliation(s)
- J P Fonfría
- Molecular Astrophysics Group, Instituto de Ciencia de Materiales de Madrid, CSIC, C/ Sor Juana Inés de la Cruz, 3, Cantoblanco, 28049, Madrid (Spain)
- Molecular Astrophysics Group, Instituto de Física Fundamental, CSIC, C/ Serrano, 123, 28006, Madrid (Spain)
| | - M Fernández-López
- Instituto Argentino de Radioastronomía, CCT-La Plata (CONICET), C.C.5, 1894, Villa Elisa (Argentina)
| | - J R Pardo
- Molecular Astrophysics Group, Instituto de Ciencia de Materiales de Madrid, CSIC, C/ Sor Juana Inés de la Cruz, 3, Cantoblanco, 28049, Madrid (Spain)
- Molecular Astrophysics Group, Instituto de Física Fundamental, CSIC, C/ Serrano, 123, 28006, Madrid (Spain)
| | - M Agúndez
- Molecular Astrophysics Group, Instituto de Ciencia de Materiales de Madrid, CSIC, C/ Sor Juana Inés de la Cruz, 3, Cantoblanco, 28049, Madrid (Spain)
- Molecular Astrophysics Group, Instituto de Física Fundamental, CSIC, C/ Serrano, 123, 28006, Madrid (Spain)
| | - C Sánchez Contreras
- Department of Astrophysics, Astrobiology Center (CSIC-INTA), Postal address: ESAC campus, P.O. Box 78, E-28691, Villanueva de la Canãda, Madrid (Spain)
| | - L Velilla Prieto
- Molecular Astrophysics Group, Instituto de Ciencia de Materiales de Madrid, CSIC, C/ Sor Juana Inés de la Cruz, 3, Cantoblanco, 28049, Madrid (Spain)
- Molecular Astrophysics Group, Instituto de Física Fundamental, CSIC, C/ Serrano, 123, 28006, Madrid (Spain)
| | - J Cernicharo
- Molecular Astrophysics Group, Instituto de Ciencia de Materiales de Madrid, CSIC, C/ Sor Juana Inés de la Cruz, 3, Cantoblanco, 28049, Madrid (Spain)
- Molecular Astrophysics Group, Instituto de Física Fundamental, CSIC, C/ Serrano, 123, 28006, Madrid (Spain)
| | - M Santander-García
- Observatorio Astronómico Nacional, OAN-IGN, Alfonso XII, 3, E-28014, Madrid (Spain)
| | - G Quintana-Lacaci
- Molecular Astrophysics Group, Instituto de Ciencia de Materiales de Madrid, CSIC, C/ Sor Juana Inés de la Cruz, 3, Cantoblanco, 28049, Madrid (Spain)
- Molecular Astrophysics Group, Instituto de Física Fundamental, CSIC, C/ Serrano, 123, 28006, Madrid (Spain)
| | - A Castro-Carrizo
- Institut de Radioastronomie Millimétrique, 300 Rue de la Piscine, 38406 Saint-Martin d'Hères (France)
| | - S Curiel
- Departamento de Astrofísica Teórica, Instituto de Astronomía, Universidad Nacional Autónoma de México, Ciudad Universitaria, 04510, Mexico City (Mexico)
| |
Collapse
|
10
|
Massalkhi S, Agúndez M, Cernicharo J, Velilla Prieto L, Goicoechea JR, Quintana-Lacaci G, Fonfría JP, Alcolea J, Bujarrabal V. The Abundance of SiC 2 in Carbon Star Envelopes: Evidence that SiC 2 is a gas-phase precursor of SiC dust. ASTRONOMY AND ASTROPHYSICS 2018; 611:A29. [PMID: 29628518 PMCID: PMC5884425 DOI: 10.1051/0004-6361/201732038] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
CONTEXT Silicon carbide dust is ubiquitous in circumstellar envelopes around C-rich AGB stars. However, the main gas-phase precursors leading to the formation of SiC dust have not yet been identified. The most obvious candidates among the molecules containing an Si-C bond detected in C-rich AGB stars are SiC2, SiC, and Si2C. To date, the ring molecule SiC2 has been observed in a handful of evolved stars, while SiC and Si2C have only been detected in the C-star envelope IRC +10216. AIMS We aim to study how widespread and abundant SiC2, SiC, and Si2C are in envelopes around C-rich AGB stars and whether or not these species play an active role as gas-phase precursors of silicon carbide dust in the ejecta of carbon stars. METHODS We carried out sensitive observations with the IRAM 30m telescope of a sample of 25 C-rich AGB stars to search for emission lines of SiC2, SiC, and Si2C in the λ 2 mm band. We performed non-LTE excitation and radiative transfer calculations based on the LVG method to model the observed lines of SiC2 and to derive SiC2 fractional abundances in the observed envelopes. RESULTS We detect SiC2 in most of the sources, SiC in about half of them, and do not detect Si2C in any source, at the exception of IRC +10216. Most of these detections are reported for the first time in this work. We find a positive correlation between the SiC and SiC2 line emission, which suggests that both species are chemically linked, the SiC radical probably being the photodissociation product of SiC2 in the external layer of the envelope. We find a clear trend in which the denser the envelope, the less abundant SiC2 is. The observed trend is interpreted as an evidence of efficient incorporation of SiC2 onto dust grains, a process which is favored at high densities owing to the higher rate at which collisions between particles take place. CONCLUSIONS The observed behavior of a decline in the SiC2 abundance with increasing density strongly suggests that SiC2 is an important gas-phase precursor of SiC dust in envelopes around carbon stars.
Collapse
Affiliation(s)
- Sarah Massalkhi
- Grupo de Astrofísica Molecular, Instituto de Ciencia de Materiales de Madrid, CSIC, C/ Sor Juana Inés de la Cruz 3, 28049, Cantoblanco, Spain
| | - M Agúndez
- Grupo de Astrofísica Molecular, Instituto de Ciencia de Materiales de Madrid, CSIC, C/ Sor Juana Inés de la Cruz 3, 28049, Cantoblanco, Spain
| | - J Cernicharo
- Grupo de Astrofísica Molecular, Instituto de Ciencia de Materiales de Madrid, CSIC, C/ Sor Juana Inés de la Cruz 3, 28049, Cantoblanco, Spain
| | - L Velilla Prieto
- Grupo de Astrofísica Molecular, Instituto de Ciencia de Materiales de Madrid, CSIC, C/ Sor Juana Inés de la Cruz 3, 28049, Cantoblanco, Spain
| | - J R Goicoechea
- Grupo de Astrofísica Molecular, Instituto de Ciencia de Materiales de Madrid, CSIC, C/ Sor Juana Inés de la Cruz 3, 28049, Cantoblanco, Spain
| | - G Quintana-Lacaci
- Grupo de Astrofísica Molecular, Instituto de Ciencia de Materiales de Madrid, CSIC, C/ Sor Juana Inés de la Cruz 3, 28049, Cantoblanco, Spain
| | - J P Fonfría
- Grupo de Astrofísica Molecular, Instituto de Ciencia de Materiales de Madrid, CSIC, C/ Sor Juana Inés de la Cruz 3, 28049, Cantoblanco, Spain
| | - J Alcolea
- Observatorio Astronómico Nacional (IGN), C/ Alfonso XII 3, 28014, Madrid, Spain
| | - V Bujarrabal
- Observatorio Astronómico Nacional (IGN), Apartado de Correos 112, 28803, Alcalá de Henares, Madrid, Spain
| |
Collapse
|
11
|
Cernicharo J, Agúndez M, Velilla Prieto L, Guélin M, Pardo JR, Kahane C, Marka C, Kramer C, Navarro S, Quintana-Lacaci G, Fonfría JP, Marcelino N, Tercero B, Moreno E, Massalkhi S, Santander-García M, McCarthy MC, Gottlieb CA, Alonso JL. Discovery of methyl silane and confirmation of silyl cyanide in IRC +10216. ASTRONOMY AND ASTROPHYSICS 2017; 606:L5. [PMID: 29142328 PMCID: PMC5683346 DOI: 10.1051/0004-6361/201731672] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
We report the discovery in space of methyl silane, CH3SiH3, from observations of ten rotational transitions between 80 and 350 GHz (Ju from 4 to 16) with the IRAM 30 m radio telescope. The molecule was observed in the envelope of the C-star IRC +10216. The observed profiles and our models for the expected emission of methyl silane suggest that the it is formed in the inner zones of the circumstellar envelope, 1-40 R*, with an abundance of (0.5-1) × 10-8 relative to H2. We also observed several rotational transitions of silyl cyanide (SiH3CN), confirming its presence in IRC +10216 in particular, and in space in general. Our models indicate that silyl cyanide is also formed in the inner regions of the envelope, around 20 R*, with an abundance relative to H2 of 6×10-10. The possible formation mechanisms of both species are discussed. We also searched for related chemical species but only upper limits could be obtained.
Collapse
Affiliation(s)
- J Cernicharo
- Group of Molecular Astrophysics, ICMM, CSIC, C/ Sor Juana Inés de La Cruz 3, 28049 Madrid, Spain
| | - M Agúndez
- Group of Molecular Astrophysics, ICMM, CSIC, C/ Sor Juana Inés de La Cruz 3, 28049 Madrid, Spain
| | - L Velilla Prieto
- Group of Molecular Astrophysics, ICMM, CSIC, C/ Sor Juana Inés de La Cruz 3, 28049 Madrid, Spain
| | - M Guélin
- Institut de Radioastronomie Millimétrique, 300 rue de la Piscine, 38406 St-Martin d'Hères, France
| | - J R Pardo
- Group of Molecular Astrophysics, ICMM, CSIC, C/ Sor Juana Inés de La Cruz 3, 28049 Madrid, Spain
| | - C Kahane
- Université Grenoble Alpes, CNRS, IPAG, 38000 Grenoble, France
| | - C Marka
- Instituto de Radioastronomía Milimétrica, Av. Divina Pastora 7, Local 20, 18012 Granada, Spain
| | - C Kramer
- Instituto de Radioastronomía Milimétrica, Av. Divina Pastora 7, Local 20, 18012 Granada, Spain
| | - S Navarro
- Instituto de Radioastronomía Milimétrica, Av. Divina Pastora 7, Local 20, 18012 Granada, Spain
| | - G Quintana-Lacaci
- Group of Molecular Astrophysics, ICMM, CSIC, C/ Sor Juana Inés de La Cruz 3, 28049 Madrid, Spain
| | - J P Fonfría
- Group of Molecular Astrophysics, ICMM, CSIC, C/ Sor Juana Inés de La Cruz 3, 28049 Madrid, Spain
| | - N Marcelino
- Group of Molecular Astrophysics, ICMM, CSIC, C/ Sor Juana Inés de La Cruz 3, 28049 Madrid, Spain
| | - B Tercero
- Group of Molecular Astrophysics, ICMM, CSIC, C/ Sor Juana Inés de La Cruz 3, 28049 Madrid, Spain
| | - E Moreno
- Group of Molecular Astrophysics, ICMM, CSIC, C/ Sor Juana Inés de La Cruz 3, 28049 Madrid, Spain
| | - S Massalkhi
- Group of Molecular Astrophysics, ICMM, CSIC, C/ Sor Juana Inés de La Cruz 3, 28049 Madrid, Spain
| | - M Santander-García
- Group of Molecular Astrophysics, ICMM, CSIC, C/ Sor Juana Inés de La Cruz 3, 28049 Madrid, Spain
| | - M C McCarthy
- Harvard-Smithsonian Center for Astrophysics, Cambridge, MA 02138, and School of Engineering & Applied Sciences, Harvard University, Cambridge, MA 02138, USA
| | - C A Gottlieb
- Harvard-Smithsonian Center for Astrophysics, Cambridge, MA 02138, and School of Engineering & Applied Sciences, Harvard University, Cambridge, MA 02138, USA
| | - 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, Universidad de Valladolid, 47011 Valladolid, Spain
| |
Collapse
|
12
|
Velilla Prieto L, Sánchez Contreras C, Cernicharo J, Agúndez M, Quintana-Lacaci G, Bujarrabal V, Alcolea J, Balança C, Herpin F, Menten KM, Wyrowski F. The millimeter IRAM-30 m line survey toward IK Tau. ASTRONOMY AND ASTROPHYSICS 2017; 597:A25. [PMID: 28008187 PMCID: PMC5166976 DOI: 10.1051/0004-6361/201628776] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
AIMS We aim to investigate the physical and chemical properties of the molecular envelope of the oxygen-rich AGB star IK Tau. METHODS We carried out a millimeter wavelength line survey between ~79 and 356 GHz with the IRAM-30 m telescope. We analysed the molecular lines detected in IK Tau using the population diagram technique to derive rotational temperatures and column densities. We conducted a radiative transfer analysis of the SO2 lines, which also helped us to verify the validity of the approximated method of the population diagram for the rest of the molecules. RESULTS For the first time in this source we detected rotational lines in the ground vibrational state of HCO+, NS, NO, and H2CO, as well as several isotopologues of molecules previously identified, namely, C18O, Si17O, Si18O, 29SiS, 30SiS, Si34S, H13CN, 13CS, C34S, H234S, 34SO, and 34SO2. We also detected several rotational lines in vibrationally excited states of SiS and SiO isotopologues, as well as rotational lines of H2O in the vibrationally excited state ν2=2. We have also increased the number of rotational lines detected of molecules that were previously identified toward IK Tau, including vibrationally excited states, enabling a detailed study of the molecular abundances and excitation temperatures. In particular, we highlight the detection of NS and H2CO with fractional abundances of f(NS)~10-8 and f(H2CO)~[10-7-10-8 ]. Most of the molecules display rotational temperatures between 15 and 40 K. NaCl and SiS isotopologues display rotational temperatures higher than the average (~65 K). In the case of SO2 a warm component with Trot~290 K is also detected. CONCLUSIONS With a total of ~350 lines detected of 34 different molecular species (including different isotopologues), IK Tau displays a rich chemistry for an oxygen-rich circumstellar envelope. The detection of carbon bearing molecules like H2CO, as well as the discrepancies found between our derived abundances and the predictions from chemical models for some molecules, highlight the need for a revision of standard chemical models. We were able to identify at least two different emission components in terms of rotational temperatures. The warm component, which is mainly traced out by SO2, is probably arising from the inner regions of the envelope (at ≲8R∗) where SO2 has a fractional abundance of f(SO2)~10-6. This result should be considered for future investigation of the main formation channels of this, and other, parent species in the inner winds of O-rich AGB stars, which at present are not well reproduced by current chemistry models.
Collapse
Affiliation(s)
- L Velilla Prieto
- Instituto de Ciencia de Materiales de Madrid, CSIC, c/ Sor Juana Inés de la Cruz 3, 28049 Cantoblanco, Madrid, Spain; Centro de Astrobiología, INTA-CSIC, E-28691 Villanueva de la Cañada, Madrid, Spain
| | - C Sánchez Contreras
- Centro de Astrobiología, INTA-CSIC, E-28691 Villanueva de la Cañada, Madrid, Spain
| | - J Cernicharo
- Instituto de Ciencia de Materiales de Madrid, CSIC, c/ Sor Juana Inés de la Cruz 3, 28049 Cantoblanco, Madrid, Spain
| | - M Agúndez
- Instituto de Ciencia de Materiales de Madrid, CSIC, c/ Sor Juana Inés de la Cruz 3, 28049 Cantoblanco, Madrid, Spain
| | - G Quintana-Lacaci
- Instituto de Ciencia de Materiales de Madrid, CSIC, c/ Sor Juana Inés de la Cruz 3, 28049 Cantoblanco, Madrid, Spain
| | - V Bujarrabal
- Observatorio Astronómico Nacional (IGN), Ap 112, 28803 Alcalá de Henares, Madrid, Spain
| | - J Alcolea
- Observatorio Astronómico Nacional (IGN), Alfonso XII No 3, 28014 Madrid, Spain
| | - C Balança
- LERMA, Observatoire de Paris, Sorbonne Université, UPMC, UMR 8112, F-92195 Meudon, France
| | - F Herpin
- Université de Bordeaux, LAB, UMR 5804, F-33270 Floirac, France; CNRS, LAB, UMR 5804, F-33270, Floirac, France
| | - K M Menten
- Max-Planck-Institut für Radioastronomie, Auf dem Hügel 69, 53121 Bonn, Germany
| | - F Wyrowski
- Max-Planck-Institut für Radioastronomie, Auf dem Hügel 69, 53121 Bonn, Germany
| |
Collapse
|
13
|
Quintana-Lacaci G, Agúndez M, Cernicharo J, Bujarrabal V, Sánchez Contreras C, Castro-Carrizo A, Alcolea J. A λ 3 mm and 1 mm line survey toward the yellow hypergiant IRC +10420: N-rich chemistry and IR flux variations. ASTRONOMY AND ASTROPHYSICS 2016; 592:A51. [PMID: 27458319 PMCID: PMC4957670 DOI: 10.1051/0004-6361/201527688] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
AIMS Our knowledge of the chemical properties of the circumstellar ejecta of the most massive evolved stars is particularly poor. We aim to study the chemical characteristics of the prototypical yellow hypergiant star, IRC +10420. For this purpose, we obtained full line surveys at 1 and 3 mm atmospheric windows. METHODS We have identified 106 molecular emission lines from 22 molecular species. Approximately half of the molecules detected are N-bearing species, in particular HCN, HNC, CN, NO, NS, PN, and N2H+. We used rotational diagrams to derive the density and rotational temperature of the different molecular species detected. We introduced an iterative method that allows us to take moderate line opacities into account. RESULTS We have found that IRC +10420 presents high abundances of the N-bearing molecules compared with O-rich evolved stars. This result supports the presence of a N-rich chemistry, expected for massive stars. Our analysis also suggests a decrease of the 12C/13C ratio from ≳ 7 to ~ 3.7 in the last 3800 years, which can be directly related to the nitrogen enrichment observed. In addition, we found that SiO emission presents a significant intensity decrease for high-J lines when compared with older observations. Radiative transfer modeling shows that this variation can be explained by a decrease in the infrared (IR) flux of the dust. The origin of this decrease might be an expansion of the dust shell or a lower stellar temperature due to the pulsation of the star.
Collapse
Affiliation(s)
- G Quintana-Lacaci
- Instituto de Ciencia de Materiales de Madrid, Sor Juana Inés de la Cruz, 3, Cantoblanco, 28049 Madrid, Spain. ,
| | - M Agúndez
- Instituto de Ciencia de Materiales de Madrid, Sor Juana Inés de la Cruz, 3, Cantoblanco, 28049 Madrid, Spain. ,
| | - J Cernicharo
- Instituto de Ciencia de Materiales de Madrid, Sor Juana Inés de la Cruz, 3, Cantoblanco, 28049 Madrid, Spain. ,
| | - V Bujarrabal
- Observatorio Astronómico Nacional (IGN), Ap 112, E-28803, Alcalá de Henares, Spain.
| | - C Sánchez Contreras
- Department of Astrophysics, Astrobiology Center (CSIC-INTA), Postal address: ESAC campus, P.O. Box 78, E-28691 Villanueva de la Cañada, Madrid, Spain.
| | - A Castro-Carrizo
- Institut de RadioAstronomie Millimétrique, 300 rue de la Piscine, 38406 Saint Martin d'Héres, France.
| | - J Alcolea
- Observatorio Astronómico Nacional (IGN), Alfonso XII N o 3, 28014 Madrid, Spain.
| |
Collapse
|
14
|
Fonfría JP, Cernicharo J, Richter MJ, Fernández-López M, Prieto LV, Lacy JH. The abundance of 28Si 32S, 29Si 32S, 28Si 34S, and 30Si 32S in the inner layers of the envelope of IRC+10216. MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY 2015; 453:439-449. [PMID: 26997679 PMCID: PMC4797415 DOI: 10.1093/mnras/stv1634] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
We present high spectral resolution mid-IR observations of SiS towards the C-rich AGB star IRC+10216 carried out with the Texas Echelon-cross-Echelle Spectrograph mounted on the NASA Infrared Telescope Facility. We have identified 204 ro-vibrational lines of 28Si32S, 26 of 29Si32S, 20 of 28Si34S, and 15 of 30Si32S in the frequency range 720 - 790 cm-1. These lines belong to bands v = 1 - 0, 2 - 1, 3 - 2, 4-3, and 5-4, and involve rotational levels with Jlow ≲ 90. About 30 per cent of these lines are unblended or weakly blended and can be partially or entirely fitted with a code developed to model the mid-IR emission of a spherically symmetric circumstellar envelope composed of expanding gas and dust. The observed lines trace the envelope at distances to the star ≲ 35R⋆(≃ 0″.7). The fits are compatible with an expansion velocity of 1+2.5(r/R⋆ -1) km s-1 between 1 and 5R⋆, 11 km s-1 between 5 and 20R⋆, and 14.5 km s-1 outwards. The derived abundance profile of 28Si32S with respect to H2 is 4.9 × 10-6 between the stellar photosphere and 5R⋆, decreasing linearly down to 1.6 × 10-6 at 20R⋆ and to 1.3 × 10-6 at 50R⋆. 28Si32S seems to be rotationally under LTE in the region of the envelope probed with our observations and vibrationally out of LTE in most of it. There is a red-shifted emission excess in the 28Si32S lines of band v = 1 - 0 that cannot be found in the lines of bands v = 2 - 1, 3 - 2, 4 - 3, and 5 - 4. This excess could be explained by an enhancement of the vibrational temperature around 20R⋆ behind the star. The derived isotopic ratios 28Si/29Si, and 32S/34S are 17 and 14, compatible with previous estimates.
Collapse
Affiliation(s)
- J. P. Fonfría
- Departamento de Estrellas y Medio Interestelar, Instituto de Astronomía, UNAM, Ciudad Universitaria, 04510, Mexico City (Mexico)
| | - J. Cernicharo
- Grupo de Astrofísica Molecular, Instituto de Ciencia de Materiales de Madrid, CSIC, C/ Sor Juana Inés de la Cruz 3, 28049, Cantoblanco, Madrid (Spain)
| | - M. J. Richter
- Physics Dept. - UC Davis, One Shields Ave., Davis, CA 95616 (USA)
| | - M. Fernández-López
- Instituto Argentino de Radioastronomía, CCT-La Plata (CONICET), C.C.5, 1894, Villa Elisa (Argentina)
| | - L. Velilla Prieto
- Grupo de Astrofísica Molecular, Instituto de Ciencia de Materiales de Madrid, CSIC, C/ Sor Juana Inés de la Cruz 3, 28049, Cantoblanco, Madrid (Spain)
| | - J. H. Lacy
- Astronomy Dept., University of Texas, Austin, TX 78712 (USA)
| |
Collapse
|
15
|
Cernicharo J, McCarthy MC, Gottlieb CA, Agúndez M, Velilla Prieto L, Baraban JH, Changala PB, Guélin M, Kahane C, Martin-Drumel MA, Patel NA, Reilly NJ, Stanton JF, Quintana-Lacaci G, Thorwirth S, Young KH. Discovery of SiCSi in IRC +10216: A missing link between gas and dust carriers of Si-C bonds. THE ASTROPHYSICAL JOURNAL. LETTERS 2015; 806:L3. [PMID: 26722621 PMCID: PMC4693961 DOI: 10.1088/2041-8205/806/1/l3] [Citation(s) in RCA: 62] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
We report the discovery in space of a disilicon species, SiCSi, from observations between 80 and 350 GHz with the IRAM 30m radio telescope. Owing to the close coordination between laboratory experiments and astrophysics, 112 lines have now been detected in the carbon-rich star CW Leo. The derived frequencies yield improved rotational and centrifugal distortion constants up to sixth order. From the line profiles and interferometric maps with the Submillimeter Array, the bulk of the SiCSi emission arises from a region of 6″ in radius. The derived abundance is comparable to that of SiC2. As expected from chemical equilibrium calculations, SiCSi and SiC2 are the most abundant species harboring a Si-C bond in the dust formation zone and certainly both play a key role in the formation of SiC dust grains.
Collapse
Affiliation(s)
- J Cernicharo
- Group of Molecular Astrophysics. ICMM. CSIC. C/Sor Juana Inés de La Cruz N3. E-28049, Madrid. Spain
| | - M C McCarthy
- Harvard-Smithsonian Center for Astrophysics, Cambridge, MA 02138, and School of Engineering & Applied Sciences, Harvard University, Cambridge, MA 02138
| | - C A Gottlieb
- Harvard-Smithsonian Center for Astrophysics, Cambridge, MA 02138, and School of Engineering & Applied Sciences, Harvard University, Cambridge, MA 02138
| | - M Agúndez
- Group of Molecular Astrophysics. ICMM. CSIC. C/Sor Juana Inés de La Cruz N3. E-28049, Madrid. Spain
| | - L Velilla Prieto
- Group of Molecular Astrophysics. ICMM. CSIC. C/Sor Juana Inés de La Cruz N3. E-28049, Madrid. Spain
| | - J H Baraban
- Department of Chemistry and Biochemistry, University of Colorado, Boulder, CO 80309
| | - P B Changala
- JILA, National Institute of Standards and Technology and University of Colorado, and Department of Physics, University of Colorado, Boulder, CO 80309
| | - M Guélin
- Institut de Radioastronomie Millimétrique, 300 rue de la Piscine, F-38406, St-Martin d'Hères, France
| | - C Kahane
- Universit Grenoble Alpes, IPAG, F-38000 Grenoble, France; CNRS, IPAG, F-38000 Grenoble, France
| | - M A Martin-Drumel
- Harvard-Smithsonian Center for Astrophysics, Cambridge, MA 02138, and School of Engineering & Applied Sciences, Harvard University, Cambridge, MA 02138
| | - N A Patel
- Harvard-Smithsonian Center for Astrophysics, Cambridge, MA 02138, and School of Engineering & Applied Sciences, Harvard University, Cambridge, MA 02138
| | - N J Reilly
- Harvard-Smithsonian Center for Astrophysics, Cambridge, MA 02138, and School of Engineering & Applied Sciences, Harvard University, Cambridge, MA 02138
| | - J F Stanton
- Institute for Theoretical Chemistry, Department of Chemistry, The University of Texas at Austin, Austin, TX 78712
| | - G Quintana-Lacaci
- Group of Molecular Astrophysics. ICMM. CSIC. C/Sor Juana Inés de La Cruz N3. E-28049, Madrid. Spain
| | - S Thorwirth
- I. Physikalisches Institut, Universität zu Köln, Zülpicher Str. 77, 50937 Köln, Germany
| | - K H Young
- Harvard-Smithsonian Center for Astrophysics, Cambridge, MA 02138, and School of Engineering & Applied Sciences, Harvard University, Cambridge, MA 02138
| |
Collapse
|
16
|
Cernicharo J, Marcelino N, Agúndez M, Guélin M. Molecular shells in IRC+10216: tracing the mass loss history ,. ASTRONOMY AND ASTROPHYSICS 2015; 575:A91. [PMID: 27069260 PMCID: PMC4826601 DOI: 10.1051/0004-6361/201424565] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/29/2023]
Abstract
Thermally-pulsating AGB stars provide three-fourths of the matter returned to the interstellar medium. The mass and chemical composition of their ejecta largely control the chemical evolution of galaxies. Yet, both the mass loss process and the gas chemical composition remain poorly understood. We present maps of the extended 12CO and 13CO emissions in IRC+10216, the envelope of CW Leo, the high mass loss star the closest to the Sun. IRC+10216 is nearly spherical and expands radially with a velocity of 14.5 km s-1. The observations were made On-the-Fly with the IRAM 30 m telescope; their sensibility, calibration, and angular resolution are far higher than all previous studies. The telescope resolution at λ = 1.3 mm (11″ HPBW) corresponds to an expansion time of 500 yr. The CO emission consists of a centrally peaked pedestal and a series of bright, nearly spherical shells. It peaks on CW Leo and remains relatively strong up to rphot = 180″. Further out the emission becomes very weak and vanishes as CO gets photodissociated. As CO is the best tracer of the gas up to rphot, the maps show the mass loss history in the last 8000 yr. The bright CO shells denote over-dense regions. They show that the mass loss process is highly variable on timescales of hundreds of years. The new data, however, do not support previous claims of a strong decrease of the average mass loss in the last few thousand years. The over-dense shells are not perfectly concentric and extend farther to the N-NW. The typical shell separation is 800-1000 yr in the middle of the envelope, but seems to increase outwards. The shell-intershell brightness contrast is ≥3. All those key features can be accounted for if CW Leo has a companion star with a period ≃800 yr that increases the mass loss rate when it comes close to periastron. Higher angular resolution observations are needed to fully resolve the dense shells and measure the density contrast. The latter plays an essential role in our understanding of the envelope chemistry.
Collapse
Affiliation(s)
- J Cernicharo
- ICMM. CSIC. Group of Molecular Astrophysics. C/ Sor Juana Inés de la Cruz 3. Cantoblanco, 28049 Madrid, Spain
| | - N Marcelino
- National Radio Astronomy Observatory, 520 Edgemont Road, Charlottesville, VA 22903, USA
| | - M Agúndez
- ICMM. CSIC. Group of Molecular Astrophysics. C/ Sor Juana Inés de la Cruz 3. Cantoblanco, 28049 Madrid, Spain
| | - M Guélin
- Institut de Radioastronomie Millimétrique, 300 rue de la Piscine, 38406 Saint Martin d'Hères, France ; LERMA, Observatoire de Paris, PSL Research University, CNRS, UMR 8112, 75014 Paris, France
| |
Collapse
|