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Chua BH, Gloesener E, Choukroun M, Vu TH, Melwani Daswani M, Journaux B, Styczinski MJ, Vance SD. Low-Temperature Specific Heat Capacity of Water-Ammonia Mixtures Down to the Eutectic. ACS Earth Space Chem 2023; 7:1971-1979. [PMID: 37876662 PMCID: PMC10591500 DOI: 10.1021/acsearthspacechem.3c00091] [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] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/10/2023] [Revised: 08/15/2023] [Accepted: 09/05/2023] [Indexed: 10/26/2023]
Abstract
Robust thermodynamic data are essential for the development of geodynamic and geochemical models of ocean worlds. The water-ammonia system is of interest in the study of ocean worlds due to its purported abundance in the outer solar system, geological implications, and potential importance for origins of life. In support of developing new equations of state, we conducted 1 bar specific heat capacity measurements (Cp) using a differential scanning calorimeter (DSC) at low temperatures (184-314 K) and low mass fractions of ammonia (5.2-26.9 wt %) to provide novel data in the parameter space most relevant for planetary studies. This is the first known set of data with sufficient fidelity to investigate the trend of specific heat capacity with respect to temperature. The obtained Cp in the liquid phase domain above the liquidus generally increases with temperature. Deviations of our data from the currently adopted equation of state by Tillner-Roth and Friend[Tillner-Roth R.; Friend D. G.J. Phys. Chem. Ref. Data1998, 27, 63-96]. are generally negative (ranging from +1 to -10%) and larger at lower temperatures. This result suggests that suppression of the critical behavior of supercooled water (rapid increase in specific heat with decreasing temperature) by ammonia starts at a smaller concentration than that set by Tillner-Roth and Friend.[Tillner-Roth R.; Friend D. G.J. Phys. Chem. Ref. Data1998, 27, 63-96]. Cp measurements of the liquid were also obtained in the partial melting domain between the eutectic and liquidus. This novel data set will be useful in future investigations of conditions where such partial melt may exist, such as the ice shell-ocean boundary or the interiors of ocean worlds that may contain relatively large proportions of dissolved ammonia.
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Affiliation(s)
- Bing Hong Chua
- Jet
Propulsion Laboratory, California Institute
of Technology, 4800 Oak Grove Drive, Pasadena, California 91109, United States
- Asian
School of the Environment, Nanyang Technological
University, 50 Nanyang
Avenue, Singapore 639798, Singapore
| | - Elodie Gloesener
- Jet
Propulsion Laboratory, California Institute
of Technology, 4800 Oak Grove Drive, Pasadena, California 91109, United States
| | - Mathieu Choukroun
- Jet
Propulsion Laboratory, California Institute
of Technology, 4800 Oak Grove Drive, Pasadena, California 91109, United States
| | - Tuan H. Vu
- Jet
Propulsion Laboratory, California Institute
of Technology, 4800 Oak Grove Drive, Pasadena, California 91109, United States
| | - Mohit Melwani Daswani
- Jet
Propulsion Laboratory, California Institute
of Technology, 4800 Oak Grove Drive, Pasadena, California 91109, United States
| | - Baptiste Journaux
- Department
of Earth and Space Sciences, University
of Washington, 4000 15th Ave NE, Seattle, Washington 98195, United States
| | - Marshall J. Styczinski
- Jet
Propulsion Laboratory, California Institute
of Technology, 4800 Oak Grove Drive, Pasadena, California 91109, United States
| | - Steven D. Vance
- Jet
Propulsion Laboratory, California Institute
of Technology, 4800 Oak Grove Drive, Pasadena, California 91109, United States
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Mahjoub A, Altwegg K, Poston MJ, Rubin M, Hodyss R, Choukroun M, Ehlmann BL, Hänni N, Brown ME, Blacksberg J, Eiler JM, Hand KP. Complex organosulfur molecules on comet 67P: Evidence from the ROSINA measurements and insights from laboratory simulations. Sci Adv 2023; 9:eadh0394. [PMID: 37285429 DOI: 10.1126/sciadv.adh0394] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/07/2023] [Accepted: 05/01/2023] [Indexed: 06/09/2023]
Abstract
The ROSINA (Rosetta Orbiter Spectrometer for Ion and Neutral Analysis) instrument aboard the Rosetta mission revolutionized our understanding of cometary material composition. One of Rosetta's key findings is the complexity of the composition of comet 67P/Churyumov-Gerasimenko. Here, we used ROSINA data to analyze dust particles that were volatilized during a dust event in September 2016 and report the detection of large organosulfur species and an increase in the abundances of sulfurous species previously detected in the coma. Our data support the presence of complex sulfur-bearing organics on the surface of the comet. In addition, we conducted laboratory simulations that show that this material may have formed from chemical reactions that were initiated by the irradiation of mixed ices containing H2S. Our findings highlight the importance of sulfur chemistry in cometary and precometary materials and the possibility of characterizing organosulfur materials in other comets and small icy bodies using the James Webb Space Telescope.
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Affiliation(s)
- Ahmed Mahjoub
- Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109, USA
- Space Science Institute, 4765 Walnut St, Suite B, Boulder, CO 80301, USA
| | - Kathrin Altwegg
- Physikalisches Institut, University of Bern, Bern, Switzerland
| | | | - Martin Rubin
- Physikalisches Institut, University of Bern, Bern, Switzerland
| | - Robert Hodyss
- Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109, USA
| | - Mathieu Choukroun
- Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109, USA
| | - Bethany L Ehlmann
- Division of Planetary and Space Sciences, Caltech, Pasadena, CA 91125, USA
| | - Nora Hänni
- Physikalisches Institut, University of Bern, Bern, Switzerland
| | - Michael E Brown
- Division of Planetary and Space Sciences, Caltech, Pasadena, CA 91125, USA
| | - Jordana Blacksberg
- Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109, USA
| | - John M Eiler
- Division of Planetary and Space Sciences, Caltech, Pasadena, CA 91125, USA
| | - Kevin P Hand
- Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109, USA
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Czaplinski EC, Vu TH, Cable ML, Choukroun M, Malaska MJ, Hodyss R. Experimental Characterization of the Pyridine:Acetylene Co-crystal and Implications for Titan's Surface. ACS Earth Space Chem 2023; 7:597-608. [PMID: 36960425 PMCID: PMC10026175 DOI: 10.1021/acsearthspacechem.2c00377] [Citation(s) in RCA: 1] [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] [Figures] [Subscribe] [Scholar Register] [Received: 12/06/2022] [Revised: 02/16/2023] [Accepted: 02/16/2023] [Indexed: 06/18/2023]
Abstract
Titan, Saturn's largest moon, has a plethora of organic compounds in the atmosphere and on the surface that interact with each other. Cryominerals such as co-crystals may influence the geologic processes and chemical composition of Titan's surface, which in turn informs our understanding of how Titan may have evolved, how the surface is continuing to change, and the extent of Titan's habitability. Previous works have shown that a pyridine:acetylene (1:1) co-crystal forms under specific temperatures and experimental conditions; however, this has not yet been demonstrated under Titan-relevant conditions. Our work here demonstrates that the pyridine:acetylene co-crystal is stable from 90 K, Titan's average surface temperature, up to 180 K under an atmosphere of N2. In particular, the co-crystal forms via liquid-solid interactions within minutes upon mixing of the constituents at 150 K, as evidenced by distinct, new Raman bands and band shifts. X-ray diffraction (XRD) results indicate moderate anisotropic thermal expansion (about 0.5-1.1%) along the three principal axes between 90-150 K. Additionally, the co-crystal is detectable after being exposed to liquid ethane, implying stability in a residual ethane "wetting" scenario on Titan. These results suggest that the pyridine:acetylene co-crystal could form in specific geologic contexts on Titan that allow for warm environments in which liquid pyridine could persist, and as such, this cryomineral may preserve the evidence of impact, cryovolcanism, or subsurface transport in surface materials.
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Choukroun M, Petuya C, Vu TH, Desmedt A, Davies AG, Sotin C. Reply to the 'Comment on Cage occupancy of methane clathrate hydrates in the ternary H 2O-NH 3-CH 4 system' by S. Alavi and J. Ripmeester, Chem. Commun., 2022, 58, DOI: 10.1039/D1CC06526B. Chem Commun (Camb) 2022; 58:4099-4102. [PMID: 35289825 DOI: 10.1039/d2cc00568a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Our recent Communication suggested that ammonia in aqueous solution may preferentially destabilize large cages in methane clathrate hydrates. A Comment favored ammonia incorporation instead, but it did not accurately describe our proposed mechanism and relied primarily on studies conducted in different chemical systems and/or which used other preparation methods.
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Affiliation(s)
- Mathieu Choukroun
- Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA, USA.
| | - Claire Petuya
- Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA, USA.
| | - Tuan H Vu
- Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA, USA.
| | - Arnaud Desmedt
- Institut des Sciences Moléculaires, CNRS UMR 5255, Talence, France
| | - Ashley Gerard Davies
- Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA, USA.
| | - Christophe Sotin
- Laboratoire de Planétologie et Géodynamique, CNRS UMR 6112, Nantes, France
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5
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Maynard-Casely HE, Hodyss R, Vu T, Malaska M, Choukroun M, Cable M, Runčevski T. Exploration of organic minerals on Saturn's moon Titan. Acta Crystallogr A Found Adv 2021. [DOI: 10.1107/s0108767321091005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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Hodyss R, Vu TH, Choukroun M, Cable ML. A simple gas introduction system for cryogenic powder X-ray diffraction. J Appl Crystallogr 2021. [DOI: 10.1107/s1600576721006671] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
Abstract
A simple system is described for the introduction of gases into standard X-ray diffraction capillaries mounted in situ in the X-ray beam of laboratory X-ray diffraction instruments. This system retains many of the advantages of the standard Norby cell, but does not require custom machining and has less stringent space restrictions. The system has been used to study the crystallization and interaction of volatile organics at cryogenic temperatures, but gas–solid interactions could also be studied at elevated temperatures using this approach.
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Vu TH, Maynard-Casely HE, Cable ML, Hodyss R, Choukroun M, Malaska MJ. Anisotropic thermal expansion of the acetylene–ammonia co-crystal under Titan's conditions. J Appl Crystallogr 2020. [DOI: 10.1107/s1600576720014028] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
Abstract
Acetylene and ammonia are known to form a stable orthorhombic co-crystal under the surface conditions of Saturn's moon Titan (1.5 bar = 150 kPa, 94 K). Such a material represents a potential new class of organic minerals that could play an important role in Titan's geology. In this work, the thermal expansion of this co-crystalline system has been derived from in situ powder X-ray diffraction data obtained between 85 and 120 K. The results indicate significant anisotropy, with the majority of the expansion occurring along the c axis (∼2% over the temperature range of interest). Rietveld refinements reveal little change to the structure compared with that previously reported by Boese, Bläser & Jansen [J. Am. Chem. Soc. (2009), 131, 2104–2106]. The expansion is consistent with the alignment of C—H...N interactions along the chains in the a and b axes, and weak intermolecular bonding in the structural layers along the c axis.
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Petuya C, Choukroun M, Vu TH, Desmedt A, Davies AG, Sotin C. Cage occupancy of methane clathrate hydrates in the ternary H 2O-NH 3-CH 4 system. Chem Commun (Camb) 2020; 56:12391-12394. [PMID: 32935703 DOI: 10.1039/d0cc04339g] [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] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The incorporation of ammonia inside methane clathrate hydrate is of great interest to the hydrate chemistry community. We investigated the phase behavior of methane clathrate formed from aqueous ammonia solution. Ammonia's presence decreases methane occupancy in the large cages, without definitive Raman spectroscopic evidence for its incorporation inside the structure.
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Affiliation(s)
- Claire Petuya
- Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA, USA.
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Abstract
The vibrational signatures for the υ2 C≡C and υ1 symmetric C-H stretches of acetylene in cubic structure I clathrate, synthesized under ambient pressure, are reported for the first time. The most diagnostic features are at 1966 for υ2 and 3353 cm-1 for υ1, respectively, and are assigned to acetylene trapped in the large 51262 cages. In addition, the υ2 mode for acetylene occupying the small 512 cages is observed at 1972.5 cm-1, a red shift of 1.5 cm-1 from its gas phase frequency. Unit cell parameters and thermal expansion coefficients are determined via powder X-ray diffraction between 195 and 225 K and are found to be in good correlation with previous single crystal data at 143 K. The calculated density for acetylene clathrate is also reported, with values ranging from 0.985 g/cm3 at 195 K to 0.976 g/cm3 at 225 K. These results are relevant for spectral detection of acetylene-containing compounds on planetary bodies, as well as providing additional insights on the thermal behavior and physical properties of acetylene clathrate.
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Affiliation(s)
- Tuan H Vu
- Jet Propulsion Laboratory , California Institute of Technology , Pasadena , California 91109 , United States
| | - Robert Hodyss
- Jet Propulsion Laboratory , California Institute of Technology , Pasadena , California 91109 , United States
| | - Morgan L Cable
- Jet Propulsion Laboratory , California Institute of Technology , Pasadena , California 91109 , United States
| | - Mathieu Choukroun
- Jet Propulsion Laboratory , California Institute of Technology , Pasadena , California 91109 , United States
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10
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Molaro JL, Choukroun M, Phillips CB, Phelps ES, Hodyss R, Mitchell KL, Lora JM, Meirion-Griffith G. The microstructural evolution of water ice in the solar system through sintering. J Geophys Res Planets 2019; 124:243-277. [PMID: 32874819 PMCID: PMC7458059 DOI: 10.1029/2018je005773] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/26/2018] [Accepted: 12/17/2018] [Indexed: 06/11/2023]
Abstract
Ice sintering is a form of metamorphism that drives the microstructural evolution of an aggregate of grains through surface and volume diffusion. This leads to an increase in the grain-to-grain contact area ("neck") and density of the aggregate over time, resulting in the evolution of its strength, porosity, thermal conductivity, and other properties. This process plays an important role in the evolution of icy planetary surfaces, though its rate and nature are not well constrained. In this study, we explore the model of Swinkels and Ashby (1981), and assess the extent to which it can be used to quantify sintering timescales for water ice. We compare predicted neck growth rates to new and historical observations of ice sintering, and find agreement to some studies at the order of magnitude level. First-order estimates of neck growth timescales on planetary surfaces show that ice may undergo significant modification over geologic timescales, even in the outer solar system. Densification occurs over much longer timescales, suggesting some surfaces may develop cohesive, but porous, crusts. Sintering rates are extremely sensitive to temperature and grain size, occurring faster in warmer aggregates of smaller grains. This suggests that the microstructural evolution of ices may vary not only throughout the solar system, but also spatially across the surface and in the near-surface of a given body. Our experimental observations of complex grain growth and mass redistribution in ice aggregates point to components of the model that may benefit from improvement, and areas where additional laboratory studies are needed.
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Affiliation(s)
- J. L. Molaro
- Planetary Science Institute, 1700 East Fort Lowell, Suite 106, Tucson, AZ 85719, USA
- Jet Propulsion Laboratory, California Institute of Technology, 4800 Oak Grove Drive, Pasadena, CA 91109, USA
| | - M. Choukroun
- Jet Propulsion Laboratory, California Institute of Technology, 4800 Oak Grove Drive, Pasadena, CA 91109, USA
| | - C. B. Phillips
- Jet Propulsion Laboratory, California Institute of Technology, 4800 Oak Grove Drive, Pasadena, CA 91109, USA
| | - E. S. Phelps
- Jet Propulsion Laboratory, California Institute of Technology, 4800 Oak Grove Drive, Pasadena, CA 91109, USA
| | - R. Hodyss
- Jet Propulsion Laboratory, California Institute of Technology, 4800 Oak Grove Drive, Pasadena, CA 91109, USA
| | - K. L. Mitchell
- Jet Propulsion Laboratory, California Institute of Technology, 4800 Oak Grove Drive, Pasadena, CA 91109, USA
| | - J. M. Lora
- University of California, Los Angeles, 595 Charles Young Drive East, Los Angeles, CA 90095, USA
| | - G. Meirion-Griffith
- Jet Propulsion Laboratory, California Institute of Technology, 4800 Oak Grove Drive, Pasadena, CA 91109, USA
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11
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Mahjoub A, Choukroun M, Hodyss R, Sotin C, Beauchamp P, Barmatz M. Titan Lakes Simulation System (TiLSS): A cryogenic experimental setup to simulate Titan's liquid hydrocarbon surfaces. Rev Sci Instrum 2018; 89:124502. [PMID: 30599566 DOI: 10.1063/1.5053126] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/21/2018] [Accepted: 11/18/2018] [Indexed: 06/09/2023]
Abstract
Titan's hydrocarbon lakes play an important role in the chemistry, geomorphology, and climate of the satellite. Our knowledge of their composition relies mainly on thermodynamic modeling and assumptions based on Cassini Radar and VIMS (Visible and Infrared Mapping Spectrometer) data. Several thermodynamic models have been used to calculate the composition of these lakes, and their results on even the major lake components (methane, ethane, propane, and nitrogen) exhibit large discrepancies. Recent Cassini radar observations revealed an echo from the lake's bottom. A low loss factor of attenuation is needed within the lakes to interpret these observations, and it has been suggested that the lakes are dominated by methane. Cassini VIMS data obtained on the North Pole lakes at three-year intervals showed no detectable surface level change, which is consistent with ethane being their primary constituent. This additional discrepancy between thermodynamic models and Cassini data strongly shows the need for experimental measurements under realistic Titan conditions in order to better constrain the thermodynamic models. We designed and built a cryogenic experimental platform allowing the simulation of Titan's lakes. This facility, named Titan Lakes Simulation System (TiLSS), produces liquid hydrocarbons in equilibrium with a gas phase mimicking Titan's atmosphere. Samples of the condensed liquid are injected directly into a gas chromatograph allowing the direct measurement of its chemical components and their abundances. To test the overall operation of the system, a gas mixture of methane and ethane was condensed under 1.5 bar of nitrogen and analyzed. Results from this proof of concept test are in good agreement with experimental studies previously published.
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Affiliation(s)
- Ahmed Mahjoub
- Jet Propulsion Laboratory, California Institute of Technology, Pasadena, California 91109, USA
| | - Mathieu Choukroun
- Jet Propulsion Laboratory, California Institute of Technology, Pasadena, California 91109, USA
| | - Robert Hodyss
- Jet Propulsion Laboratory, California Institute of Technology, Pasadena, California 91109, USA
| | - Christophe Sotin
- Jet Propulsion Laboratory, California Institute of Technology, Pasadena, California 91109, USA
| | - Patricia Beauchamp
- Jet Propulsion Laboratory, California Institute of Technology, Pasadena, California 91109, USA
| | - Martin Barmatz
- Jet Propulsion Laboratory, California Institute of Technology, Pasadena, California 91109, USA
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12
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Maynard-Casely HE, Cable M, Malaska M, Vu T, Choukroun M, Hodyss R. Prospects for organic minerals on Saturn's moon Titan. Acta Crystallogr A Found Adv 2017. [DOI: 10.1107/s2053273317082754] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
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13
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Taylor MGGT, Altobelli N, Buratti BJ, Choukroun M. The Rosetta mission orbiter science overview: the comet phase. Philos Trans A Math Phys Eng Sci 2017; 375:rsta.2016.0262. [PMID: 28554981 PMCID: PMC5454230 DOI: 10.1098/rsta.2016.0262] [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] [Accepted: 03/07/2017] [Indexed: 05/11/2023]
Abstract
The international Rosetta mission was launched in 2004 and consists of the orbiter spacecraft Rosetta and the lander Philae. The aim of the mission is to map the comet 67P/Churyumov-Gerasimenko by remote sensing, and to examine its environment in situ and its evolution in the inner Solar System. Rosetta was the first spacecraft to rendezvous with and orbit a comet, accompanying it as it passes through the inner Solar System, and to deploy a lander, Philae, and perform in situ science on the comet's surface. The primary goals of the mission were to: characterize the comet's nucleus; examine the chemical, mineralogical and isotopic composition of volatiles and refractories; examine the physical properties and interrelation of volatiles and refractories in a cometary nucleus; study the development of cometary activity and the processes in the surface layer of the nucleus and in the coma; detail the origin of comets, the relationship between cometary and interstellar material and the implications for the origin of the Solar System; and characterize asteroids 2867 Steins and 21 Lutetia. This paper presents a summary of mission operations and science, focusing on the Rosetta orbiter component of the mission during its comet phase, from early 2014 up to September 2016.This article is part of the themed issue 'Cometary science after Rosetta'.
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Affiliation(s)
| | - N Altobelli
- ESA/ESAC, 28692 Villanueva de la Cañada, Spain
| | - B J Buratti
- JPL/California Institute of Technology, Pasadena, CA 91109, USA
| | - M Choukroun
- JPL/California Institute of Technology, Pasadena, CA 91109, USA
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14
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Gulkis S, Allen M, von Allmen P, Beaudin G, Biver N, Bockelée-Morvan D, Choukroun M, Crovisier J, Davidsson BJR, Encrenaz P, Encrenaz T, Frerking M, Hartogh P, Hofstadter M, Ip WH, Janssen M, Jarchow C, Keihm S, Lee S, Lellouch E, Leyrat C, Rezac L, Schloerb FP, Spilker T. Cometary science. Subsurface properties and early activity of comet 67P/Churyumov-Gerasimenko. Science 2015; 347:aaa0709. [PMID: 25613896 DOI: 10.1126/science.aaa0709] [Citation(s) in RCA: 202] [Impact Index Per Article: 22.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
Heat transport and ice sublimation in comets are interrelated processes reflecting properties acquired at the time of formation and during subsequent evolution. The Microwave Instrument on the Rosetta Orbiter (MIRO) acquired maps of the subsurface temperature of comet 67P/Churyumov-Gerasimenko, at 1.6 mm and 0.5 mm wavelengths, and spectra of water vapor. The total H2O production rate varied from 0.3 kg s(-1) in early June 2014 to 1.2 kg s(-1) in late August and showed periodic variations related to nucleus rotation and shape. Water outgassing was localized to the "neck" region of the comet. Subsurface temperatures showed seasonal and diurnal variations, which indicated that the submillimeter radiation originated at depths comparable to the diurnal thermal skin depth. A low thermal inertia (~10 to 50 J K(-1) m(-2) s(-0.5)), consistent with a thermally insulating powdered surface, is inferred.
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Affiliation(s)
- Samuel Gulkis
- Jet Propulsion Laboratory/California Institute of Technology, 4800 Oak Grove Drive, Pasadena, CA 91109, USA.
| | - Mark Allen
- Jet Propulsion Laboratory/California Institute of Technology, 4800 Oak Grove Drive, Pasadena, CA 91109, USA
| | - Paul von Allmen
- Jet Propulsion Laboratory/California Institute of Technology, 4800 Oak Grove Drive, Pasadena, CA 91109, USA
| | - Gerard Beaudin
- LERMA, Observatoire de Paris, PSL Research University, UPMC Université Paris 06, CNRS, UMR8112, F-75014 Paris, France
| | - Nicolas Biver
- LESIA-Observatoire de Paris, CNRS, UPMC, Université Paris-Diderot, 5 place Jules Janssen, 92195 Meudon, France
| | - Dominique Bockelée-Morvan
- LESIA-Observatoire de Paris, CNRS, UPMC, Université Paris-Diderot, 5 place Jules Janssen, 92195 Meudon, France
| | - Mathieu Choukroun
- Jet Propulsion Laboratory/California Institute of Technology, 4800 Oak Grove Drive, Pasadena, CA 91109, USA
| | - Jacques Crovisier
- LESIA-Observatoire de Paris, CNRS, UPMC, Université Paris-Diderot, 5 place Jules Janssen, 92195 Meudon, France
| | - Björn J R Davidsson
- Department of Physics and Astronomy, Uppsala University, Box 516, SE-75120 Uppsala, Sweden
| | - Pierre Encrenaz
- LERMA, Observatoire de Paris, PSL Research University, UPMC Université Paris 06, CNRS, UMR8112, F-75014 Paris, France
| | - Therese Encrenaz
- LESIA-Observatoire de Paris, CNRS, UPMC, Université Paris-Diderot, 5 place Jules Janssen, 92195 Meudon, France
| | - Margaret Frerking
- Jet Propulsion Laboratory/California Institute of Technology, 4800 Oak Grove Drive, Pasadena, CA 91109, USA
| | - Paul Hartogh
- Max-Planck-Institut für Sonnensystemforschung, Justus-von-Liebig-Weg 3, 37077 Göttingen, Germany
| | - Mark Hofstadter
- Jet Propulsion Laboratory/California Institute of Technology, 4800 Oak Grove Drive, Pasadena, CA 91109, USA
| | - Wing-Huen Ip
- National Central University, Jhongli, Taoyuan City 32001, Taiwan
| | - Michael Janssen
- Jet Propulsion Laboratory/California Institute of Technology, 4800 Oak Grove Drive, Pasadena, CA 91109, USA
| | - Christopher Jarchow
- Max-Planck-Institut für Sonnensystemforschung, Justus-von-Liebig-Weg 3, 37077 Göttingen, Germany
| | - Stephen Keihm
- Jet Propulsion Laboratory/California Institute of Technology, 4800 Oak Grove Drive, Pasadena, CA 91109, USA
| | - Seungwon Lee
- Jet Propulsion Laboratory/California Institute of Technology, 4800 Oak Grove Drive, Pasadena, CA 91109, USA
| | - Emmanuel Lellouch
- LESIA-Observatoire de Paris, CNRS, UPMC, Université Paris-Diderot, 5 place Jules Janssen, 92195 Meudon, France
| | - Cedric Leyrat
- LESIA-Observatoire de Paris, CNRS, UPMC, Université Paris-Diderot, 5 place Jules Janssen, 92195 Meudon, France
| | - Ladislav Rezac
- Max-Planck-Institut für Sonnensystemforschung, Justus-von-Liebig-Weg 3, 37077 Göttingen, Germany
| | - F Peter Schloerb
- University of Massachusetts, 619 Lederle Graduate Research Tower, Amherst, MA 01003, USA. Jet Propulsion Laboratory/California Institute of Technology, 4800 Oak Grove Drive, Pasadena, CA 91109, USA
| | - Thomas Spilker
- Jet Propulsion Laboratory/California Institute of Technology, 4800 Oak Grove Drive, Pasadena, CA 91109, USA
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Vu TH, Gloesener E, Choukroun M, Ibourichene A, Hodyss R. Experimental Study on the Effect of Ammonia on the Phase Behavior of Tetrahydrofuran Clathrates. J Phys Chem B 2014; 118:13371-7. [DOI: 10.1021/jp5042487] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Tuan Hoang Vu
- NASA
Jet Propulsion Laboratory, California Institute of Technology, 4800 Oak
Grove Drive, Pasadena, California 91109, United States
| | - Elodie Gloesener
- Observatoire Royal de Belgique, Avenue
Circulaire 3, 1180 Uccle, Belgium
| | - Mathieu Choukroun
- NASA
Jet Propulsion Laboratory, California Institute of Technology, 4800 Oak
Grove Drive, Pasadena, California 91109, United States
| | | | - Robert Hodyss
- NASA
Jet Propulsion Laboratory, California Institute of Technology, 4800 Oak
Grove Drive, Pasadena, California 91109, United States
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Vu TH, Cable ML, Choukroun M, Hodyss R, Beauchamp P. Formation of a New Benzene–Ethane Co-Crystalline Structure Under Cryogenic Conditions. J Phys Chem A 2014; 118:4087-94. [DOI: 10.1021/jp501698j] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Affiliation(s)
- Tuan Hoang Vu
- NASA Jet
Propulsion Laboratory, California Institute of Technology, 4800 Oak
Grove Drive, Pasadena, California 91109, United States
| | - Morgan L. Cable
- NASA Jet
Propulsion Laboratory, California Institute of Technology, 4800 Oak
Grove Drive, Pasadena, California 91109, United States
| | - Mathieu Choukroun
- NASA Jet
Propulsion Laboratory, California Institute of Technology, 4800 Oak
Grove Drive, Pasadena, California 91109, United States
| | - Robert Hodyss
- NASA Jet
Propulsion Laboratory, California Institute of Technology, 4800 Oak
Grove Drive, Pasadena, California 91109, United States
| | - Patricia Beauchamp
- NASA Jet
Propulsion Laboratory, California Institute of Technology, 4800 Oak
Grove Drive, Pasadena, California 91109, United States
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Siegler M, Aharonson O, Carey E, Choukroun M, Hudson T, Schorghofer N, Xu S. Measurements of thermal properties of icy Mars regolith analogs. ACTA ACUST UNITED AC 2012. [DOI: 10.1029/2011je003938] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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Choukroun M, Grasset O. Thermodynamic data and modeling of the water and ammonia-water phase diagrams up to 2.2 GPa for planetary geophysics. J Chem Phys 2010; 133:144502. [DOI: 10.1063/1.3487520] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
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Tobie G, Choukroun M, Grasset O, Le Mouélic S, Lunine JI, Sotin C, Bourgeois O, Gautier D, Hirtzig M, Lebonnois S, Le Corre L. Evolution of Titan and implications for its hydrocarbon cycle. Philos Trans A Math Phys Eng Sci 2009; 367:617-631. [PMID: 19073458 DOI: 10.1098/rsta.2008.0246] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
Measurements of the carbon and nitrogen isotopic ratios as well as the detection of 40Ar and 36Ar by the gas chromatograph mass spectrometer (GCMS) instrument on board the Huygens probe have provided key constraints on the origin and evolution of Titan's atmosphere, and indirectly on the evolution of its interior. Those data combined with models of Titan's interior can be used to determine the story of volatile outgassing since Titan's formation. In the absence of an internal source, methane, which is irreversibly photodissociated in Titan's stratosphere, should be removed entirely from the atmosphere in a time-span of a few tens of millions of years. The episodic destabilization of methane clathrate reservoir stored within Titan's crust and subsequent methane outgassing could explain the present atmospheric abundance of methane, as well as the presence of argon in the atmosphere. The idea that methane is released from the interior through eruptive processes is also supported by the observations of several cryovolcanic-like features on Titan's surface by the mapping spectrometer (VIMS) and the radar on board Cassini. Thermal instabilities within the icy crust, possibly favoured by the presence of ammonia, may explain the observed features and provide the conditions for eruption of methane and other volatiles. Episodic resurfacing events associated with thermal and compositional instabilities in the icy crust can have major consequences on the hydrocarbon budget on Titan's surface and atmosphere.
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Affiliation(s)
- G Tobie
- Laboratoire de Planétologie et Géodynamique de Nantes, Université Nantes Atlantique, 2, rue de la Houssinière, 44322 Nantes Cedex 03, France CNRS, UMR-6112, 2, rue de la Houssinière, 44322 Nantes Cedex 03, France.
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Abstract
We propose a thermodynamic model of the properties of liquid water and ices I, III, V, and VI that can be used in the ranges of 0-2200 MPa and 180-360 K. This model is the first to be applicable to all H(2)O phases in these wide ranges, which exceed the stability domain of all phases. Developing empirical or semiempirical expressions for the specific volumes of liquid water or ices has been necessary. The model has been tested on available experimental data sets. The specific volume of liquid water is reproduced with an accuracy better than 1%. The error on the specific volume of ices remains within 2%. The model has also been used to describe the melting curves of high-pressure ice polymorphs and compared with new Simon equations fitting available data. Our calculations suggest a slight revision of the triple point positions in the H(2)O phase diagram. We have ensured the reliability of our model up to 1.5 GPa, and we have shown that it can be used with good confidence up to 2.2 GPa. In order to show the validity of this model in the low-temperature domains, the melting curve of ice Ih in the water-ammonia system has been modeled. This curve is reproduced with good accuracy down to 180 K, at a 1 bar pressure. It shows that this model can be used in further studies for modeling equilibriums involving liquid or solid phases of H(2)O under pressure and for investigating the effect of inhibitors in complex water-rich systems.
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Affiliation(s)
- Mathieu Choukroun
- UMR-CNRS 6112-Laboratoire de Planétologie et Géodynamique de Nantes, Université de Nantes, 2 rue de la Houssinière, 44322 Nantes Cedex 3, France.
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Choukroun M. [Not Available]. Rev Hist Med Heb 1985; 38:30-3. [PMID: 11637232] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/22/2023]
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