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1. Gas composition of main volatile elements in protoplanetary discs and its implication for planet formation

Author: Amaury, Thiabaud, Ulysse, Marboeuf, Yann, Alibert, Ingo, Leya, and Klaus, Mezger
Subjects: Astrophysics - Earth and Planetary Astrophysics
Abstract: Direct observations of gaseous exoplanets reveals that their gas envelope is commonly enriched in C/O ratio compared to that of the host star. This has been explained by considering that the gas phase of the disc could be inhomogeneous, exceeding the stellar C/O ratio in regions where these planets formed; but few studies have considered the drift of the gas and the migration of planets. We aim to derive the gas composition in planets to evaluate if the formation of giant planets with an enriched C/O ratio is possible. The study focusses on the effects of different processes on the C/O ratio like the disc evolution, the drift of gas, and the migration of the planet. We used our previous models for computation of the chemical composition together with the planet formation model of Alibert et al. (2013), to which we added the composition and drift of the gas phase of the disc composed of major volatile species, H2 and He. The study focusses on the region where ice lines are present and influence the C/O ratio of the planets. Modelling shows that the condensation of volatile species allows for C/O enrichment in specific parts of the protoplanetary disc, of up to 4 times the solar value. This leads to the formation of planets that can be enriched in C/O in their envelope up to 3 times the solar value. The migration of planets, the evolution of the gas phase, and the irradiation of the disc enables the evolution of the initial C/O ratio with a decrease in the outer part of the disc and an increase in the inner part. The total C/O ratio of the planets is governed by the contribution of ices accreted, suggesting that high C/O ratios measured in planetary atmospheres are indicative of a lack of exchange of material between the core of a planet and its envelope or an observational bias, and suggesting that the observed C/O ratio is not representative of the total C/O ratio of the planet., Comment: 12 pages, 15 figures. Accepted for publication in A&A
Published: 2014
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2. Isotopic ratios D/H and 15N/14N in giant planets

Author: Ulysse Marboeuf, Amaury Thiabaud, Yann Alibert, and Willy Benz
Subjects: Physics, Planetesimal, 010504 meteorology & atmospheric sciences, Isotope, Gas giant, Astronomy and Astrophysics, 01 natural sciences, Accretion (astrophysics), Astrobiology, 13. Climate action, Space and Planetary Science, Planet, 0103 physical sciences, Astrophysics::Solar and Stellar Astrophysics, Astrophysics::Earth and Planetary Astrophysics, Great conjunction, 010303 astronomy & astrophysics, Relative species abundance, 0105 earth and related environmental sciences, Envelope (waves)
Abstract: The determination of isotopic ratios in planets is important since it allows us to investigate the origins and initial composition of materials. The present work aims to determine the possible range of values for isotopic ratios D/H and ¹⁵N/¹⁴N in giant planets. The main objective is to provide valuable theoretical assumptions on the isotopic composition of giant planets, their internal structure, and the main reservoirs of species. We use models of ice formation and planet formation that compute the composition of ices and gas accreted in the core and the envelope of planets. Assuming a single initial value for isotopic ratios in volatile species, and disruption of planetesimals in the envelope of gaseous planets, we obtain a wide variety of D/H and ¹⁵N/¹⁴N ratios in low-mass planets (≤100 Mearth) due to the migration pathway of planets, the accretion time of gas species whose relative abundance evolves with time, and isotope exchanges among species. If giant planets with mass greater than 100 Mearth have solar isotopic ratios such as Jupiter and Saturn due to their higher envelope mass, Neptune-type planets present values ranging between one and three times the solar value. It seems therefore difficult to use isotopic ratios in the envelope of these planets to get information about their formation in the disc. For giant planets, the ratios allow us to constrain the mass fraction of volatile species in the envelope needed to reproduce the observational data by assuming initial values for isotopic ratios in volatile species.
Published: 2017
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3. Radial Drift and Concurrent Ablation of Boulder-Sized Objects

Author: Ulysse Marboeuf, Willy Benz, Remo Burn, and Yann Alibert
Subjects: Physics, Earth and Planetary Astrophysics (astro-ph.EP), 010504 meteorology & atmospheric sciences, Thermodynamic equilibrium, FOS: Physical sciences, Astronomy and Astrophysics, Astrophysics, Protoplanetary disk, 01 natural sciences, Accretion (astrophysics), 13. Climate action, Space and Planetary Science, Planet, 0103 physical sciences, Thermal, Snow line, Sublimation (phase transition), Solid body, Astrophysics::Earth and Planetary Astrophysics, 010303 astronomy & astrophysics, Astrophysics::Galaxy Astrophysics, 0105 earth and related environmental sciences, Astrophysics - Earth and Planetary Astrophysics
Abstract: Context. The composition of a protoplanetary disk at a given location does not only depend on temperature and pressure but also on the time dependent transport of matter, such as radial drift of solid bodies, which could release water and other volatile species before disintegration or accretion onto a larger body with potentially considerable implications for the composition of planets. Aims. We perform a parameter study focused on the water depletion of different sized bodies able to cross the water snowline by gas induced radial drift. Methods. Either the analytical Hertz-Knudsen-Langmuir sublimation formula assuming equilibrium temperature within the body or a more involved, numerical model for the internal thermal evolution is coupled with an alpha-disk model. Different properties of the disk and the embedded body are explored. Results. Bodies with radii up to 100 meter drift faster towards the central star than the water snowline, hence, cross it. The region that can be reached before complete disintegration - and is therefore polluted with H2O ice - extends to 10 percent closer to the star than the snowline location. The extent of this polluted region could be multiple times larger in the presence of a dust mantle, which is, however, unlikely to form due to frequent collisions with smaller-than centimeter sized objects. Conclusions. Given a significant abundance of meter sized boulders in protoplanetary disks, the transport of water by radial drift of these bodies towards regions closer to the star than the snowline is not negligible and this flux of volatiles can be estimated for a given distribution of solid body sizes and compositions. A simple expression for surface sublimation is applicable for a homogeneous body consisting of only dust and water ice without a dust mantle., 17 pages, 17 figures, accepted for publication in Astronomy and Astrophysics
Published: 2019

4. Laboratory Studies Towards Understanding Comets

Author: Bastian Gundlach, Olivier Mousis, Martin A. Cordiner, Ulysse Marboeuf, Irakli Simonia, Fabrice Duvernay, Steven B. Charnley, Rui Yang, Thierry Chiavassa, Grégoire Danger, Patrice Theulé, Tsitsino Simonia, Murthy S. Gudipati, Ninette Abou Mrad, Paul Hartogh, Jürgen Blum, Aix Marseille Université (AMU), Jet Propulsion Laboratory (JPL), California Institute of Technology (CALTECH)-NASA, Physique des interactions ioniques et moléculaires (PIIM), Aix Marseille Université (AMU)-Centre National de la Recherche Scientifique (CNRS), Technische Universität Braunschweig = Technical University of Braunschweig [Braunschweig], NASA Goddard Space Flight Center (GSFC), Laboratoire d'Astrophysique de Marseille (LAM), Aix Marseille Université (AMU)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS), Max Planck Institute for Solar System Research (MPS), Max-Planck-Gesellschaft, Univers, Transport, Interfaces, Nanostructures, Atmosphère et environnement, Molécules (UMR 6213) (UTINAM), Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université de Franche-Comté (UFC), Université Bourgogne Franche-Comté [COMUE] (UBFC)-Université Bourgogne Franche-Comté [COMUE] (UBFC), Chemistry Department, Fudan University, 20 Handan Road, Shanghai 200433,China, Fudan University [Shanghai], NASA-California Institute of Technology (CALTECH), Technische Universität Braunschweig [Braunschweig], Laboratoire d'astrophysique de l'observatoire de Besançon (LAOB), Lab-STICC_ENSTAB_CID_IHSEV, OSM, Pôle STIC [Brest] (STIC), École Nationale Supérieure de Techniques Avancées Bretagne (ENSTA Bretagne)-École Nationale Supérieure de Techniques Avancées Bretagne (ENSTA Bretagne)-Laboratoire des sciences et techniques de l'information, de la communication et de la connaissance (Lab-STICC), École Nationale d'Ingénieurs de Brest (ENIB)-Université de Bretagne Sud (UBS)-Université de Brest (UBO)-Télécom Bretagne-Institut Brestois du Numérique et des Mathématiques (IBNM), Université de Brest (UBO)-Université européenne de Bretagne - European University of Brittany (UEB)-École Nationale Supérieure de Techniques Avancées Bretagne (ENSTA Bretagne)-Institut Mines-Télécom [Paris] (IMT)-Centre National de la Recherche Scientifique (CNRS)-École Nationale d'Ingénieurs de Brest (ENIB)-Université de Bretagne Sud (UBS)-Université de Brest (UBO)-Télécom Bretagne-Institut Brestois du Numérique et des Mathématiques (IBNM), Université de Brest (UBO)-Université européenne de Bretagne - European University of Brittany (UEB)-Institut Mines-Télécom [Paris] (IMT)-Centre National de la Recherche Scientifique (CNRS), Max-Planck-Institut für Sonnensystemforschung = Max Planck Institute for Solar System Research (MPS), Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Aix Marseille Université (AMU)-Centre National d'Études Spatiales [Toulouse] (CNES), Université de Franche-Comté (UFC), and Université Bourgogne Franche-Comté [COMUE] (UBFC)-Université Bourgogne Franche-Comté [COMUE] (UBFC)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)
Subjects: Physics, Origin of water on Earth, Comet dust, Comet, [SDU.ASTR.EP]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Earth and Planetary Astrophysics [astro-ph.EP], Astronomy, Astronomy and Astrophysics, [PHYS.ASTR.SR]Physics [physics]/Astrophysics [astro-ph]/Solar and Stellar Astrophysics [astro-ph.SR], Table (information), Astrobiology, Planetary science, [SDU]Sciences of the Universe [physics], 13. Climate action, Space and Planetary Science, Abiogenesis, Comet nucleus, [CHIM.OTHE]Chemical Sciences/Other, ComputingMilieux_MISCELLANEOUS, Line (formation)
Abstract: International audience; This review presents some of the recent advancements in our understanding of comets facilitated by laboratory studies, need for new laboratory simulations, and predictions for future explorations. With the spacecraft Rosetta at the comet 67P/Churyumov–Gerasimenko, a large volume of science data is expected to follow early results that have been published recently. The most surprising of them being hard ice shell that bounced thelander Philae a couple of times before settling on the comet. Long evaded molecular nitrogen has now been detected in the comet 67P/CG. The observed density of 470 kgm−3 is in line with other comet observations, whereas the nature and composition of hydrocarbons detected on the surface are still a puzzle. Observation of D/H ratio that deviates significantly from Earth’s water D/H ratio brings back to the table the long-standing question whether or not water on Earth was delivered by comet impacts. Our review summarizes some of the critical laboratory work that helps improve our understanding of cometary interior (whether amorphous or crystalline or containing clathrates), cometary surface (rich of complex organics), cometary coma and tail (D/H ratio, negative ions, and photoluminescence). Outstanding questions are also discussed.
Published: 2015
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5. Laboratory Studies Towards Understanding Comets

Author: Murthy S. Gudipati, Ninette Abou Mrad, Jürgen Blum, Steven B. Charnley, Thierry Chiavassa, Martin A. Cordiner, Olivier Mousis, Grégoire Danger, Fabrice Duvernay, Bastian Gundlach, Paul Hartogh, Ulysse Marboeuf, Irakli Simonia, Tsitsino Simonia, Patrice Theulé, and Rui Yang
Subjects: 010504 meteorology & atmospheric sciences, 0103 physical sciences, 010303 astronomy & astrophysics, 01 natural sciences, 0105 earth and related environmental sciences
Published: 2017
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6. How to link the relative abundances of gas species in coma of comets to their initial chemical composition?

Author: Ulysse Marboeuf and Bernard Schmitt
Subjects: Earth and Planetary Astrophysics (astro-ph.EP), Solar System, Chemistry, Comet, Clathrate hydrate, FOS: Physical sciences, Astronomy and Astrophysics, Mantle (geology), Astrobiology, Outgassing, medicine.anatomical_structure, Space and Planetary Science, medicine, Astrophysics::Earth and Planetary Astrophysics, Chemical composition, Relative species abundance, Nucleus, Physics::Atmospheric and Oceanic Physics, Astrophysics - Earth and Planetary Astrophysics
Abstract: Comets are expected to be the most primitive objects in the Solar System. The chemical composition of these objects is frequently assumed to be directly provided by the observations of the abundances of volatile molecules in the coma. The present work aims to determine the relationship between the chemical composition of the coma, the outgassing profile of volatile molecules and the internal chemical composition, and water ice structure of the nucleus, and physical assumptions on comets. To do this, we have developed a quasi 3D model of a cometary nucleus which takes into account all phase changes and water ice structures (amorphous, crystalline, clathrate, and a mixture of them); we have applied this model to the Comet 67P/Churyumov-Gerasimenko, the target of the Rosetta mission. We find that the outgassing profile of volatile molecules is a strong indicator of the physical and thermal properties (water ice structure, thermal inertia, abundances, distribution, physical differentiation) of the solid nucleus. Day/night variations of the rate of production of species helps to distinguish the clathrate structure from other water ice structures in nuclei, implying different thermodynamic conditions of cometary ice formation in the protoplanetary disc. The relative abundance (to H 2 O) of volatile molecules released from the nucleus interior varies by some orders of magnitude as a function of the distance to the Sun, the volatility of species, their abundance and distribution between the ”trapped” and ”condensed” states, the structure of water ice, and the thermal inertia and other physical assumptions (dust mantle, …) on the nucleus. For the less volatile molecules such as CO 2 and H 2 S, the relative (to H 2 O) abundance of species in coma remain similar to the primitive composition of the nucleus (relative deviation less than 25%) only around the perihelion passage (in the range −3 to −2 to +2–3 AU), whatever is the water ice structure and chemical composition, and under the conditions that the nucleus is not fully covered by a dust mantle. The relative (to H 2 O) abundance of highly volatile molecules such as CO and CH 4 in the coma remain approximately equal to the primitive nucleus composition only for nuclei made of clathrates. The nucleus releases systematically lower relative abundances of highly volatile species (up to one order of magnitude) around perihelion (in the range −3 to −2 to +2–3 AU) in the cases of the crystalline and amorphous water ice structures in the nuclei. The rate of production, the outgassing profile and the relative abundances (to H 2 O) of volatile molecules are the key parameters allowing one to retrieve the chemical composition and thermodynamic conditions of cometary ice formation in the early Solar System. The coming observations of the coma and nucleus by the Rosetta mission instruments (VIRTIS, MIRO, …) should provide the necessary constraints to the model to allow it to infer the primordial ice structure and composition of the comet.
Published: 2014
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7. Cometary ices in forming protoplanetary disc midplanes

Author: Daniel Harsono, Kenji Furuya, Ulysse Marboeuf, Catherine Walsh, Ewine F. van Dishoeck, Amaury Thiabaud, Maria Drozdovskaya, and R. Visser
Subjects: Planetesimal, Solar System, Astrochemistry, 010504 meteorology & atmospheric sciences, 530 Physics, FOS: Physical sciences, Astrophysics, 01 natural sciences, Astrobiology, Planet, Phase (matter), 0103 physical sciences, Protostar, Astrophysics::Solar and Stellar Astrophysics, 010303 astronomy & astrophysics, Solar and Stellar Astrophysics (astro-ph.SR), Physics::Atmospheric and Oceanic Physics, Astrophysics::Galaxy Astrophysics, 0105 earth and related environmental sciences, Earth and Planetary Astrophysics (astro-ph.EP), Physics, 520 Astronomy, Photodissociation, Astronomy and Astrophysics, 620 Engineering, Astrophysics - Solar and Stellar Astrophysics, Space and Planetary Science, Astrophysics::Earth and Planetary Astrophysics, Formation and evolution of the Solar System, Astrophysics - Earth and Planetary Astrophysics
Abstract: Low-mass protostars are the extrasolar analogues of the natal Solar System. Sophisticated physicochemical models are used to simulate the formation of two protoplanetary discs from the initial prestellar phase, one dominated by viscous spreading and the other by pure infall. The results show that the volatile prestellar fingerprint is modified by the chemistry en route into the disc. This holds relatively independent of initial abundances and chemical parameters: physical conditions are more important. The amount of CO2 increases via the grain-surface reaction of OH with CO, which is enhanced by photodissociation of H2O ice. Complex organic molecules are produced during transport through the envelope at the expense of CH3OH ice. Their abundances can be comparable to that of methanol ice (few % of water ice) at large disc radii (R > 30 AU). Current Class II disc models may be underestimating the complex organic content. Planet population synthesis models may underestimate the amount of CO2 and overestimate CH3OH ices in planetesimals by disregarding chemical processing between the cloud and disc phases. The overall C/O and C/N ratios differ between the gas and solid phases. The two ice ratios show little variation beyond the inner 10 AU and both are nearly solar in the case of pure infall, but both are sub-solar when viscous spreading dominates. Chemistry in the protostellar envelope en route to the protoplanetary disc sets the initial volatile and prebiotically-significant content of icy planetesimals and cometary bodies. Comets are thus potentially reflecting the provenances of the midplane ices in the Solar Nebula., Accepted for publication in MNRAS; 19 pages, 7 figures, 6 tables
Published: 2016
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8. Subsurface characterization of 67P/Churyumov-Gerasimenko's abydos site

Author: Aurélie Guilbert-Lepoutre, Ulysse Marboeuf, Simeon Barber, O. Mousis, Pierre Vernazza, Geraint Morgan, Andrew Morse, Laurent Jorda, Philippe Lamy, Ian Wright, Adrienn Luspay-Kuti, Dan Andrews, B. Brugger, Simon Sheridan, Kathleen Mandt, Laboratoire d'Astrophysique de Marseille (LAM), Aix Marseille Université (AMU)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS), Planetary and Space Sciences Research Institute [Milton Keynes] (PSSRI), Centre for Earth, Planetary, Space and Astronomical Research [Milton Keynes] (CEPSAR), The Open University [Milton Keynes] (OU)-The Open University [Milton Keynes] (OU), Center for Space and Habitability (CSH), University of Bern, Univers, Transport, Interfaces, Nanostructures, Atmosphère et environnement, Molécules (UMR 6213) (UTINAM), Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université de Franche-Comté (UFC), Université Bourgogne Franche-Comté [COMUE] (UBFC)-Université Bourgogne Franche-Comté [COMUE] (UBFC), Space Science and Engineering Division [San Antonio], Southwest Research Institute [San Antonio] (SwRI), Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Aix Marseille Université (AMU)-Centre National d'Études Spatiales [Toulouse] (CNES), Université de Franche-Comté (UFC), and Université Bourgogne Franche-Comté [COMUE] (UBFC)-Université Bourgogne Franche-Comté [COMUE] (UBFC)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)
Subjects: Physics, Earth and Planetary Astrophysics (astro-ph.EP), 010504 meteorology & atmospheric sciences, Comet, FOS: Physical sciences, Astronomy and Astrophysics, Astrophysics, Orbital period, 01 natural sciences, medicine.anatomical_structure, 13. Climate action, Space and Planetary Science, Comet nucleus, Phase (matter), 0103 physical sciences, Amorphous ice, medicine, Diffusion (business), [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], 010303 astronomy & astrophysics, Nucleus, Astrophysics - Earth and Planetary Astrophysics, 0105 earth and related environmental sciences, Dimensionless quantity
Abstract: On November 12, 2014, the ESA/Rosetta descent module Philae landed on the Abydos site of comet 67P/Churyumov-Gerasimenko. Aboard this module, the Ptolemy mass spectrometer measured a CO/CO2 ratio of 0.07 +/- 0.04 which differs substantially from the value obtained in the coma by the Rosetta/ROSINA instrument, suggesting a heterogeneity in the comet nucleus. To understand this difference, we investigated the physico-chemical properties of the Abydos subsurface leading to CO/CO2 ratios close to that observed by Ptolemy at the surface of this region. We used a comet nucleus model that takes into account different water ice phase changes (amorphous ice, crystalline ice and clathrates), as well as diffusion of molecules throughout the pores of the matrix. The input parameters of the model were optimized for the Abydos site and the ROSINA CO/CO2 measured ratio is assumed to correspond to the bulk value in the nucleus. We find that all considered structures of water ice are able to reproduce the Ptolemy observation with a time difference not exceeding ~50 days, i.e. lower than ~2% on 67P/Churyumov-Gerasimenko's orbital period. The suspected heterogeneity of 67P/Churyumov-Gerasimenko's nucleus is also found possible only if it is constituted of crystalline ices. If the icy phase is made of amorphous ice or clathrates, the difference between Ptolemy and ROSINA's measurements would rather originate from the spatial variations in illumination on the nucleus surface. An eventual new measurement of the CO/CO2 ratio at Abydos by Ptolemy could be decisive to distinguish between the three water ice structures., Comment: 5 pages, 5 figures - Accepted for publication in The Astrophysical Journal
Published: 2016
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9. Equilibrium Pressure of Ethane, Acetylene, and Krypton Clathrate Hydrates below the Freezing Point of Water

Author: Ulysse Marboeuf, Nicolas Fray, O. Brissaud, D. Gautier, Dominique Bockelée-Morvan, and Bernard Schmitt
Subjects: General Chemical Engineering, Cryostasis, Clathrate hydrate, Krypton, Inorganic chemistry, Thermodynamics, chemistry.chemical_element, General Chemistry, Icy moon, Dissociation (chemistry), Freezing point, chemistry.chemical_compound, Acetylene, chemistry, Molecule
Abstract: We report measurements of the equilibrium pressure of single guest clathrate hydrates of C2H6, C2H2, and Kr at low temperatures (mainly in the range (150 to 230) K). The results are compared with other data reported in the literature and used to determine new empirical correlation laws allowing to calculate the equilibrium pressure of clathrates of these species at any temperature below the freezing point of water. Enthalpies of clathrate formation/dissociation for these molecules are estimated using the Clausius–Clapeyron equation and show good agreement with previous reported calorimetric measurements. These results are of particular interest for studies of extraterrestrial ice-rich environments such as comets and icy moons in the solar system.
Published: 2012
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10. Hydrogen sulfide clathrate hydrate FTIR spectroscopy: A help gas for clathrate formation in the Solar System?

Author: Emmanuel Dartois, Ph. Duret, Bernard Schmitt, and Ulysse Marboeuf
Subjects: Carbon dioxide clathrate, Solar System, Chemistry, Infrared, Hydrogen sulfide, Clathrate hydrate, Infrared spectroscopy, Astronomy and Astrophysics, Astrobiology, chemistry.chemical_compound, Chemical engineering, Space and Planetary Science, Fourier transform infrared spectroscopy, Spectroscopy
Abstract: Clathrate hydrates may affect the stability and evolution of volatile species in comets and planets. Among abundant volatiles species, hydrogen sulfide forms one of the most stable clathrate hydrate and may play a major role in the initiation of the clathration process, as well as significantly affect the fraction of each volatiles species encaged in the clathrate structure with respect to the initial gaseous reservoir. In this study we investigate the hydrogen sulfide clathrate hydrate infrared signatures. Several pure and co-mixed hydrogen sulfide clathrate hydrates are produced and analyzed by infrared spectroscopy. The H2S clathrate hydrate specific vibrational transitions are recorded for an potential future search in planetary science and astrophysics, and its role as a clathrate hydrate promoter addressed.
Published: 2012
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11. Pressure dependent trace gas trapping in amorphous water ice at 77 K: Implications for determining conditions of comet formation

Author: Eric Quirico, Bernard Schmitt, Ulysse Marboeuf, and Reika Yokochi
Subjects: Materials science, Sea ice growth processes, Space and Planetary Science, Chemical physics, Interstellar ice, Amorphous ice, Deposition (phase transition), Astronomy and Astrophysics, Partial pressure, Water vapor, Astrobiology, Amorphous solid, Trace gas
Abstract: The nature of cometary volatile materials is subject to debate. Theoretical models of cometary nuclei and laboratory studies suggest that these objects could be made of amorphous water ice in addition to other volatile molecules and refractory grains. This water ice structure has the ability to encapsulate the gases of surrounding environment, reflecting the physical and chemical conditions during their deposition. Therefore, the knowledge of the chemical composition of volatile molecules trapped in amorphous water ice provides a tool for probing the formation environment of cometary ice grains. Experimental studies of gas trapping efficiency in amorphous water ice have been previously conducted mostly under kinetic conditions, where dynamic pumping and temperature gradients prevented rigorous calibrations. In this work, we investigated the trapping efficiencies of Ar, CO, CH4, Kr and N2 by depositing water vapor as ice in the presence of trace gases in a volume submerged in liquid nitrogen at 77 K. The gas trapping efficiencies were determined simply by monitoring the pressure difference of the trace gases before and after the deposition of a known amount of water molecules as amorphous ice. Our results show that the trapped gas to water molecule ratio in amorphous ice is controlled primarily by the partial pressure of the gas during water ice deposition, and is independent of the ice deposition rate as well as the gas to water ratio in the vapor phase. The trapping efficiencies of gases decrease in the order of Kr > CH4 > CO > Ar > N2 in accordance with previous studies. Assuming that the water ice structure of comets is at least partially amorphous water ice at the time of their formation, these results suggest that the total pressure and composition of the surrounding environment of amorphous ice formation are significant controlling factors of trace gas concentrations in cometary ice. This further indicates that the evolution of the solar nebula and timing of cometary ice condensation can also be important parameters in linking the volatile contents of comets and their formation process.
Published: 2012
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12. Equilibrium Data of Methane, Carbon Dioxide, and Xenon Clathrate Hydrates below the Freezing Point of Water. Applications to Astrophysical Environments

Author: O. Brissaud, Ulysse Marboeuf, Bernard Schmitt, and Nicolas Fray
Subjects: Carbon dioxide clathrate, Chemistry, General Chemical Engineering, Condensation, Clathrate hydrate, chemistry.chemical_element, Thermodynamics, General Chemistry, Methane, Freezing point, chemistry.chemical_compound, Xenon, Carbon dioxide, Physical chemistry, Formation and evolution of the Solar System
Abstract: This work reports new measurements of the three-phase (ice + clathrate hydrate + vapor) equilibrium in the systems of water and each of the following guest species: xenon from (167.20 to 246.16) K, carbon dioxide from (172.28 to 182.15) K, and methane from (145.75 to 195.74) K. The results are compared with the corresponding data reported in the literature and are used to determine empirical laws allowing the equilibrium pressure of these pure clathrates to be calculated at any temperature relevant to the astrophysical environments below the freezing point of water. These relations can be used in astrophysical models such as those devoted to the studies of the cooling and condensation of the solar nebula or to the ones of the physical evolution and gas production from cometary nuclei.
Published: 2010
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13. Origin of volatiles in the main belt

Author: Franck Selsis, Jonathan Horner, Yann Alibert, Ulysse Marboeuf, Benoit Carry, Christophe Dumas, O. Mousis, and Daniel Hestroffer
Subjects: Physics, Planetesimal, Nebula, Clathrate hydrate, Astronomy and Astrophysics, Astrophysics, Accretion (astrophysics), Temperature and pressure, 13. Climate action, Space and Planetary Science, Asteroid, Physics::Space Physics, Astrophysics::Solar and Stellar Astrophysics, Astrophysics::Earth and Planetary Astrophysics, Formation and evolution of the Solar System
Abstract: We propose a scenario for the formation of the Main Belt in which asteroids incorporated icy particles formed in the outer Solar Nebula. We calculate the composition of icy planetesimals formed beyond a heliocentric distance of 5 AU in the nebula by assuming that the abundances of all elements, in particular that of oxygen, are solar. As a result, we show that ices formed in the outer Solar Nebula are composed of a mix of clathrate hydrates, hydrates formed above 50 K and pure condensates produced at lower temperatures. We then consider the inward migration of solids initially produced in the outer Solar Nebula and show that a significant fraction may have drifted to the current position of the Main Belt without encountering temperature and pressure conditions high enough to vaporize the ices they contain. We propose that, through the detection and identification of initially buried ices revealed by recent impacts on the surfaces of asteroids, it could be possible to infer the thermodynamic conditions that were present within the Solar Nebula during the accretion of these bodies, and during the inward migration of icy planetesimals. We also investigate the potential influence that the incorporation of ices in asteroids may have on their porosities and densities. In particular, we show how the presence of ices reduces the value of the bulk density of a given body, and consequently modifies its macro-porosity from that which would be expected from a given taxonomic type.
Published: 2007
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14. Elemental ratios in stars vs planets

Author: Klaus Mezger, Yann Alibert, Ulysse Marboeuf, Ingo Leya, and Amaury Thiabaud
Subjects: 010504 meteorology & atmospheric sciences, FOS: Physical sciences, Context (language use), Astrophysics, 01 natural sciences, Luminosity, Physics - Geophysics, Planet, 0103 physical sciences, 550 Earth sciences & geology, Gibbs energy minimization, Astrophysics::Solar and Stellar Astrophysics, 010303 astronomy & astrophysics, Chemical composition, Solar and Stellar Astrophysics (astro-ph.SR), Astrophysics::Galaxy Astrophysics, 0105 earth and related environmental sciences, Physics, Earth and Planetary Astrophysics (astro-ph.EP), Solar mass, 520 Astronomy, Astronomy and Astrophysics, 620 Engineering, Geophysics (physics.geo-ph), Stars, Astrophysics - Solar and Stellar Astrophysics, 13. Climate action, Space and Planetary Science, Astrophysics::Earth and Planetary Astrophysics, Astrophysics - Earth and Planetary Astrophysics
Abstract: Context. The chemical composition of planets is an important constraint for planet formation and subsequent differentiation. While theoretical studies try to derive the compositions of planets from planet formation models in order to link the composition and formation process of planets, other studies assume that the elemental ratios in the formed planet and in the host star are the same. Aims. Using a chemical model combined with a planet formation model, we aim to link the composition of stars with solar mass and luminosity with the composition of the hosted planets. For this purpose, we study the three most important elemental ratios that control the internal structure of a planet: Fe/Si, Mg/Si, and C/O. Methods. A set of 18 different observed stellar compositions was used to cover a wide range of these elemental ratios. The Gibbs energy minimization assumption was used to derive the composition of planets, taking stellar abundances as proxies for nebular abundances, and to generate planets in a self-consistent planet formation model. We computed the elemental ratios Fe/Si, Mg/Si and C/O in three types of planets (rocky, icy, and giant planets) formed in different protoplanetary discs, and compared them to stellar abundances. Results. We show that the elemental ratios Mg/Si and Fe/Si in planets are essentially identical to those in the star. Some deviations are shown for planets that formed in specific regions of the disc, but the relationship remains valid within the ranges encompassed in our study. The C/O ratio shows only a very weak dependence on the stellar value., 8 pages, 5 figures, 3 tables. Accepted for publication in A&A
Published: 2015

15. Kinetics of hydrogen/deuterium exchanges in cometary ices

Author: Bernard Schmitt, M. Faure, Ulysse Marboeuf, Eric Quirico, Alexandre Faure, Patrice Theulé, Institut des Nanosciences de Paris (INSP), Université Pierre et Marie Curie - Paris 6 (UPMC)-Centre National de la Recherche Scientifique (CNRS), Institut de Planétologie et d'Astrophysique de Grenoble (IPAG ), Observatoire des Sciences de l'Univers de Grenoble (OSUG), Université Joseph Fourier - Grenoble 1 (UJF)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Institut national des sciences de l'Univers (INSU - CNRS)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Université Joseph Fourier - Grenoble 1 (UJF)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Institut national des sciences de l'Univers (INSU - CNRS)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS), Physique des interactions ioniques et moléculaires (PIIM), Aix Marseille Université (AMU)-Centre National de la Recherche Scientifique (CNRS), Univers, Transport, Interfaces, Nanostructures, Atmosphère et environnement, Molécules (UMR 6213) (UTINAM), Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université de Franche-Comté (UFC), Université Bourgogne Franche-Comté [COMUE] (UBFC)-Université Bourgogne Franche-Comté [COMUE] (UBFC), Institut de Planétologie et d'Astrophysique de Grenoble (IPAG), Centre National d'Études Spatiales [Toulouse] (CNES)-Université Grenoble Alpes (UGA)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire des Sciences de l'Univers de Grenoble (OSUG), Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Joseph Fourier - Grenoble 1 (UJF)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes (UGA)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Joseph Fourier - Grenoble 1 (UJF)-Centre National de la Recherche Scientifique (CNRS), Université de Franche-Comté (UFC)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS), Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Observatoire des Sciences de l'Univers de Grenoble (OSUG), Université Joseph Fourier - Grenoble 1 (UJF)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Institut national des sciences de l'Univers (INSU - CNRS)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Université Joseph Fourier - Grenoble 1 (UJF)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Institut national des sciences de l'Univers (INSU - CNRS)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS), Centre National de la Recherche Scientifique (CNRS)-Aix Marseille Université (AMU), Université de Franche-Comté (UFC), and Université Bourgogne Franche-Comté [COMUE] (UBFC)-Université Bourgogne Franche-Comté [COMUE] (UBFC)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)
Subjects: Hydrogen, Proton, [SDU.ASTR]Sciences of the Universe [physics]/Astrophysics [astro-ph], Hydrogen bond, Ices, Comet, Kinetics, nucleus, chemistry.chemical_element, Astronomy and Astrophysics, law.invention, [CHIM.THEO]Chemical Sciences/Theoretical and/or physical chemistry, chemistry, Deuterium, 13. Climate action, Space and Planetary Science, law, IR spectroscopy, composition, origin, Comets, Molecule, Physical chemistry, Atomic physics, Crystallization
Abstract: International audience; The D/H composition of volatile molecules composing cometary ices brings key constraints on the origin of comets, on the extent of their presolar heritage, as well as on the origin of atmospheres and hydro-spheres of terrestrial planets. Nevertheless, the D/H composition may have been modified to various extents in the nucleus when a comet approaches the Sun and experiences deep physical and chemical modifications in its subsurface. We question here the evolution of the D/H ratio of organic species by proton exchanges with water ice. We experimentally studied the kinetics of D/H exchanges on the ice mixtures H 2 O:CD 3 OD, H 2 O:CD 3 ND 2 and D 2 O:HCN. Our results show that fast exchanges occur on the –OH and –NH 2 chemical groups, which are processed through hydrogen bonds exchanges with water and by the molecular mobility triggered by structural changes, such as glass transition or crystallization. D/H exchanges kinetic is best described by a second-order kinetic law with activation energies of 4300 ± 900 K and 3300 ± 100 K for H 2 O:CD 3 OD and H 2 O:CD 3 ND 2 ice mixtures, respectively. The corresponding pre-exponential factors ln(A(s À1)) are 25 ± 7 and 20 ± 1, respectively. No exchange was observed in the case of HCN trapped in D 2 O ice. These results strongly suggest that upon thermal heating (1) –OH and –NH 2 chemical groups of any organic molecules loose their primordial D/H composition and equilibrate with water ice, (2) HCN does not experience proton transfer and keeps a primordial D/H composition and (3) C–H chemical groups are not isotopically modified.
Published: 2015
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16. Gas composition of main volatile elements in protoplanetary discs and its implication for planet formation

Author: Klaus Mezger, Ulysse Marboeuf, Amaury Thiabaud, Ingo Leya, and Yann Alibert
Subjects: Physics, Earth and Planetary Astrophysics (astro-ph.EP), 530 Physics, 520 Astronomy, Condensation, FOS: Physical sciences, Astronomy and Astrophysics, Context (language use), Astrophysics, 620 Engineering, Exoplanet, humanities, 13. Climate action, Space and Planetary Science, Planet, Gas composition, Astrophysics::Earth and Planetary Astrophysics, Volatiles, Chemical composition, 550 Earth sciences & geology, Astrophysics::Galaxy Astrophysics, Planetary migration, Astrophysics - Earth and Planetary Astrophysics
Abstract: Direct observations of gaseous exoplanets reveals that their gas envelope is commonly enriched in C/O ratio compared to that of the host star. This has been explained by considering that the gas phase of the disc could be inhomogeneous, exceeding the stellar C/O ratio in regions where these planets formed; but few studies have considered the drift of the gas and the migration of planets. We aim to derive the gas composition in planets to evaluate if the formation of giant planets with an enriched C/O ratio is possible. The study focusses on the effects of different processes on the C/O ratio like the disc evolution, the drift of gas, and the migration of the planet. We used our previous models for computation of the chemical composition together with the planet formation model of Alibert et al. (2013), to which we added the composition and drift of the gas phase of the disc composed of major volatile species, H2 and He. The study focusses on the region where ice lines are present and influence the C/O ratio of the planets. Modelling shows that the condensation of volatile species allows for C/O enrichment in specific parts of the protoplanetary disc, of up to 4 times the solar value. This leads to the formation of planets that can be enriched in C/O in their envelope up to 3 times the solar value. The migration of planets, the evolution of the gas phase, and the irradiation of the disc enables the evolution of the initial C/O ratio with a decrease in the outer part of the disc and an increase in the inner part. The total C/O ratio of the planets is governed by the contribution of ices accreted, suggesting that high C/O ratios measured in planetary atmospheres are indicative of a lack of exchange of material between the core of a planet and its envelope or an observational bias, and suggesting that the observed C/O ratio is not representative of the total C/O ratio of the planet., 12 pages, 15 figures. Accepted for publication in A&A
Published: 2014
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17. From stellar nebula to planets: the refractory components

Author: Yann Alibert, Klaus Mezger, Ulysse Marboeuf, Amaury Thiabaud, Ingo Leya, and Nahuel Cabral
Subjects: Solar System, Astrochemistry, 010504 meteorology & atmospheric sciences, FOS: Physical sciences, Context (language use), Astrophysics, 01 natural sciences, Astrobiology, Physics - Space Physics, Planet, 0103 physical sciences, 010303 astronomy & astrophysics, Chemical composition, 550 Earth sciences & geology, 0105 earth and related environmental sciences, Physics, Earth and Planetary Astrophysics (astro-ph.EP), Nebula, 520 Astronomy, Refractory metals, Astronomy and Astrophysics, 620 Engineering, humanities, Space Physics (physics.space-ph), 13. Climate action, Space and Planetary Science, Terrestrial planet, Astrophysics::Earth and Planetary Astrophysics, Astrophysics - Earth and Planetary Astrophysics
Abstract: We computed the abundance of refractory elements in planetary bodies formed in stellar systems with solar chemical composition by combining models for chemical composition and planet formation. We also consider the formation of refractory organic compounds, which have been ignored in previous studies on this topic. We used the commercial software package HSC Chemistry in order to compute the condensation sequence and chemical composition of refractory minerals incorporated into planets. The problem of refractory organic material is approached with two distinct model calculations: the first considers that the fraction of atoms used in the formation of organic compounds is removed from the system (i.e. organic compounds are formed in the gas phase and are nonreactive); and the second assumes that organic compounds are formed by the reaction between different compounds that had previously condensed from the gas phase. Results show that refractory material represents more than 50 wt % of the mass of solids accreted by the simulated planets, with up to 30 wt % of the total mass composed of refractory organic compounds. Carbide and silicate abundances are consistent with C/O and Mg/Si elemental ratios of 0.5 and 1.02 for the Sun. Less than 1 wt % of carbides; pyroxene and olivine in similar quantities are formed. The model predicts planets that are similar in composition to those of the Solar system. It also shows that, starting from a common initial nebula composition, a wide variety of chemically different planets can form, which means that the differences in planetary compositions are due to differences in the planetary formation process. We show that a model in which refractory organic material is absent from the system is more compatible with observations. The use of a planet formation model is essential to form a wide diversity of planets in a consistent way., Comment: 18 pages, 29 figures. Accepted for publication in A&A
Published: 2013
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18. A cometary nucleus model taking into account all phase changes of water ice: amorphous, crystalline, and clathrate

Author: Bernard Schmitt, Ulysse Marboeuf, Jean-Marc Petit, O. Mousis, Nicolas Fray, Institut de Planétologie et d'Astrophysique de Grenoble (IPAG ), Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Observatoire des Sciences de l'Univers de Grenoble (OSUG), Université Joseph Fourier - Grenoble 1 (UJF)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Institut national des sciences de l'Univers (INSU - CNRS)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Université Joseph Fourier - Grenoble 1 (UJF)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Institut national des sciences de l'Univers (INSU - CNRS)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS), Univers, Transport, Interfaces, Nanostructures, Atmosphère et environnement, Molécules (UMR 6213) (UTINAM), Université de Franche-Comté (UFC), Université Bourgogne Franche-Comté [COMUE] (UBFC)-Université Bourgogne Franche-Comté [COMUE] (UBFC)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS), Laboratoire Interuniversitaire des Systèmes Atmosphériques (LISA (UMR_7583)), Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris Diderot - Paris 7 (UPD7)-Université Paris-Est Créteil Val-de-Marne - Paris 12 (UPEC UP12)-Centre National de la Recherche Scientifique (CNRS), Observatoire des Sciences de l'Univers de Grenoble (OSUG), Université Joseph Fourier - Grenoble 1 (UJF)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Institut national des sciences de l'Univers (INSU - CNRS)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Université Joseph Fourier - Grenoble 1 (UJF)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Institut national des sciences de l'Univers (INSU - CNRS)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS), Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université de Franche-Comté (UFC), Université Bourgogne Franche-Comté [COMUE] (UBFC)-Université Bourgogne Franche-Comté [COMUE] (UBFC), Institut de Planétologie et d'Astrophysique de Grenoble (IPAG), Centre National d'Études Spatiales [Toulouse] (CNES)-Université Grenoble Alpes (UGA)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire des Sciences de l'Univers de Grenoble (OSUG), Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Joseph Fourier - Grenoble 1 (UJF)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes (UGA)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Joseph Fourier - Grenoble 1 (UJF)-Centre National de la Recherche Scientifique (CNRS), Institut UTINAM (Univers, transport, interfaces, nanostructures, atmosphère et environnement, molécules) (Besançon), Université de Franche-Comté (UFC)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS), Université Paris-Est Créteil Val-de-Marne - Paris 12 (UPEC UP12)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS), and Centre National de la Recherche Scientifique (CNRS)-Université Paris Diderot - Paris 7 (UPD7)-Université Paris-Est Créteil Val-de-Marne - Paris 12 (UPEC UP12)-Institut national des sciences de l'Univers (INSU - CNRS)
Subjects: Carbon dioxide clathrate, Physics, 010504 meteorology & atmospheric sciences, [PHYS.ASTR.EP]Physics [physics]/Astrophysics [astro-ph]/Earth and Planetary Astrophysics [astro-ph.EP], Comet, Clathrate hydrate, Astronomy and Astrophysics, Astrophysics, Protoplanetary disk, 01 natural sciences, law.invention, Astrobiology, Outgassing, 13. Climate action, Space and Planetary Science, law, Chemical physics, 0103 physical sciences, Amorphous ice, Sublimation (phase transition), Crystallization, 010303 astronomy & astrophysics, ComputingMilieux_MISCELLANEOUS, 0105 earth and related environmental sciences
Abstract: Context. Current theories, models of cometary nuclei and of ice formation in the protoplanetary disk, and laboratory studies suggest that cometary materials could be formed of pure crystalline water ice, amorphous water ice, clathrate hydrate, or a mixture of these structures of water ice. However, current models of cometary nuclei consider only two forms of ice during the thermodynamic evolution of comets: amorphous and crystalline water ices. Aims. In this work, we have developed a model of cometary nucleus that takes into account all water ice structures and phase changes in order to predict the outgassing profile of volatile molecules that could be measured by the Rosetta mission and can be used to constrain the structural type of ice existing in the interior of the Comet 67P/Churyumov-Gerasimenko, the target comet of the Rosetta mission, and, hopefully, its initial composition.Methods. We added the physic of formation/dissociation of clathrate hydrates in addition to others physical processes that are taken into account in models without clathrate hydrates. All thermal changes, as well as the release and trapping of gas with water phase changes are taken into account.Results. This model describes heat transmission, latent heat exchanges, all water ices structures and transitions (amorphous-to-pure crystalline, amorphous-to-clathrate hydrates and pure crystalline-to-clathrate hydrates and vise versa), sublimation/recondensation of volatile molecules in the nucleus, gas diffusion, gas released and trapped by crystallization and clathrate formation/dissociation processes, as well as gas and dust release and mantle formation at the surface. Applying this model to the comet 67P/Churyumov-Gerasimenko, results show different outgassing profiles of volatiles molecules from the nucleus depending on the water ice structure, the distribution of volatile molecules between the “trapped” and “condensed” states in the nucleus and the thermal inertia of its porous matrix. Conclusions. Given these results, we pretend that this model is able to constrain the water ice structure and chemical composition in comets from outgassing profiles of volatile molecules, and especially those of the target comet of the Rosetta mission.
Published: 2012
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19. On the Volatile Enrichments and Heavy Element Content in HD 189733b

Author: Vincent Boudon, Jean-Marc Petit, O. Mousis, Sylvain Picaud, Kevin Zahnle, J. Mitchell, Daniel Cordier, Caitlin A. Griffith, Torrence V. Johnson, Ulysse Marboeuf, Mark S. Marley, Robert Georges, Jonathan I. Lunine, Ludovic Biennier, Michel Devel, N. Iro, Univers, Transport, Interfaces, Nanostructures, Atmosphère et environnement, Molécules ( UTINAM ), Institut national des sciences de l'Univers ( INSU - CNRS ) -Centre National de la Recherche Scientifique ( CNRS ) -Université de Franche-Comté ( UFC ), Dipartimento di Fisica [Roma La Sapienza], Università degli Studi di Roma 'La Sapienza' [Rome], Department of Physics and Astronomy, University of British Columbia ( UBC ), NASA Ames Research Center ( ARC ), Institut de Physique de Rennes ( IPR ), Université de Rennes 1 ( UR1 ), Université de Rennes ( UNIV-RENNES ) -Université de Rennes ( UNIV-RENNES ) -Centre National de la Recherche Scientifique ( CNRS ), Jet Propulsion Laboratory ( JPL ), NASA-California Institute of Technology ( CALTECH ), Laboratoire Interdisciplinaire Carnot de Bourgogne ( LICB ), Université de Bourgogne ( UB ) -Centre National de la Recherche Scientifique ( CNRS ), Université européenne de Bretagne ( UEB ), Institut des Sciences Chimiques de Rennes ( ISCR ), Université de Rennes ( UNIV-RENNES ) -Université de Rennes ( UNIV-RENNES ) -Ecole Nationale Supérieure de Chimie de Rennes-Institut National des Sciences Appliquées ( INSA ) -Centre National de la Recherche Scientifique ( CNRS ), Franche-Comté Électronique Mécanique, Thermique et Optique - Sciences et Technologies ( FEMTO-ST ), Université de Technologie de Belfort-Montbeliard ( UTBM ) -Ecole Nationale Supérieure de Mécanique et des Microtechniques ( ENSMM ) -Centre National de la Recherche Scientifique ( CNRS ) -Université de Franche-Comté ( UFC ), Lunar and Planetary Laboratory [Tucson], University of Arizona, NASA Goddard Space Flight Center ( GSFC ), Univers, Transport, Interfaces, Nanostructures, Atmosphère et environnement, Molécules (UMR 6213) (UTINAM), Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université de Franche-Comté (UFC), Université Bourgogne Franche-Comté [COMUE] (UBFC)-Université Bourgogne Franche-Comté [COMUE] (UBFC), Università degli Studi di Roma 'La Sapienza' = Sapienza University [Rome], Department of Physics and Astronomy [Vancouver], University of British Columbia (UBC), NASA Ames Research Center (ARC), Institut de Physique de Rennes (IPR), Université de Rennes 1 (UR1), Université de Rennes (UNIV-RENNES)-Université de Rennes (UNIV-RENNES)-Centre National de la Recherche Scientifique (CNRS), Jet Propulsion Laboratory (JPL), NASA-California Institute of Technology (CALTECH), Laboratoire Interdisciplinaire Carnot de Bourgogne (LICB), Université de Bourgogne (UB)-Centre National de la Recherche Scientifique (CNRS), Université européenne de Bretagne - European University of Brittany (UEB), Institut des Sciences Chimiques de Rennes (ISCR), Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC)-Université de Rennes 1 (UR1), Université de Rennes (UNIV-RENNES)-Université de Rennes (UNIV-RENNES)-Ecole Nationale Supérieure de Chimie de Rennes (ENSCR)-Institut National des Sciences Appliquées - Rennes (INSA Rennes), Institut National des Sciences Appliquées (INSA)-Université de Rennes (UNIV-RENNES)-Institut National des Sciences Appliquées (INSA), Franche-Comté Électronique Mécanique, Thermique et Optique - Sciences et Technologies (UMR 6174) (FEMTO-ST), Université de Technologie de Belfort-Montbeliard (UTBM)-Ecole Nationale Supérieure de Mécanique et des Microtechniques (ENSMM)-Université de Franche-Comté (UFC), Université Bourgogne Franche-Comté [COMUE] (UBFC)-Université Bourgogne Franche-Comté [COMUE] (UBFC)-Centre National de la Recherche Scientifique (CNRS), Lunar and Planetary Laboratory [Tucson] (LPL), NASA Goddard Space Flight Center (GSFC), Université de Franche-Comté (UFC), Université Bourgogne Franche-Comté [COMUE] (UBFC)-Université Bourgogne Franche-Comté [COMUE] (UBFC)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS), Service d'Endocrinologie, Diabétologie et Maladies Métaboliques (CHU de Dijon), Centre Hospitalier Universitaire de Dijon - Hôpital François Mitterrand (CHU Dijon), Laboratoire d'astrophysique de l'observatoire de Besançon (UMR 6091) (LAOB), Université de Rennes (UNIV-RENNES), Ecole Nationale Supérieure de Chimie de Rennes (ENSCR), Institut de Planétologie et d'Astrophysique de Grenoble (IPAG ), Observatoire des Sciences de l'Univers de Grenoble (OSUG), Université Joseph Fourier - Grenoble 1 (UJF)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Institut national des sciences de l'Univers (INSU - CNRS)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Université Joseph Fourier - Grenoble 1 (UJF)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Institut national des sciences de l'Univers (INSU - CNRS)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS), Ecole Nationale Supérieure de Chimie de Rennes, Laboratoire de Planétologie de Grenoble ( LPG ), Université Joseph Fourier - Grenoble 1 ( UJF ) -Institut national des sciences de l'Univers ( INSU - CNRS ) -Centre National de la Recherche Scientifique ( CNRS ), Università degli Studi di Roma 'La Sapienza' = Sapienza University [Rome] (UNIROMA), Université de Rennes (UR)-Centre National de la Recherche Scientifique (CNRS), Laboratoire Interdisciplinaire Carnot de Bourgogne (ICB), Université de Rennes (UR)-Institut National des Sciences Appliquées - Rennes (INSA Rennes), Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Ecole Nationale Supérieure de Chimie de Rennes (ENSCR)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), Université de Technologie de Belfort-Montbeliard (UTBM)-Ecole Nationale Supérieure de Mécanique et des Microtechniques (ENSMM)-Centre National de la Recherche Scientifique (CNRS)-Université de Franche-Comté (UFC), Université Bourgogne Franche-Comté [COMUE] (UBFC)-Université Bourgogne Franche-Comté [COMUE] (UBFC)-Ecole Nationale Supérieure de Mécanique et des Microtechniques (ENSMM)-Centre National de la Recherche Scientifique (CNRS)-Université de Technologie de Belfort-Montbeliard (UTBM), Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Observatoire des Sciences de l'Univers de Grenoble (OSUG), and Centre National de la Recherche Scientifique (CNRS)-Université Joseph Fourier - Grenoble 1 (UJF)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Université Joseph Fourier - Grenoble 1 (UJF)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])
Subjects: Planetesimal, 010504 meteorology & atmospheric sciences, stars: abundances, [PHYS.ASTR.EP]Physics [physics]/Astrophysics [astro-ph]/Earth and Planetary Astrophysics [astro-ph.EP], [SDU.ASTR.EP]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Earth and Planetary Astrophysics [astro-ph.EP], chemistry.chemical_element, FOS: Physical sciences, Astrophysics, Protoplanetary disk, 01 natural sciences, Planet, 0103 physical sciences, Hot Jupiter, Astrophysics::Solar and Stellar Astrophysics, planets and satellites: formation, 010303 astronomy & astrophysics, Instrumentation and Methods for Astrophysics (astro-ph.IM), ComputingMilieux_MISCELLANEOUS, Astrophysics::Galaxy Astrophysics, 0105 earth and related environmental sciences, Envelope (waves), Physics, Earth and Planetary Astrophysics (astro-ph.EP), [ PHYS ] Physics [physics], protoplanetary disks, Giant planet, planets and satellites: composition, Astronomy and Astrophysics, planets and satellites: general, planets and satellites: individual (HD189733b), [ SDU.ASTR.EP ] Sciences of the Universe [physics]/Astrophysics [astro-ph]/Earth and Planetary Astrophysics [astro-ph.EP], Accretion (astrophysics), [CHIM.THEO]Chemical Sciences/Theoretical and/or physical chemistry, chemistry, [ PHYS.ASTR.EP ] Physics [physics]/Astrophysics [astro-ph]/Earth and Planetary Astrophysics [astro-ph.EP], 13. Climate action, Space and Planetary Science, [ CHIM.THEO ] Chemical Sciences/Theoretical and/or physical chemistry, Astrophysics::Earth and Planetary Astrophysics, Astrophysics - Instrumentation and Methods for Astrophysics, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], Carbon, Astrophysics - Earth and Planetary Astrophysics
Abstract: Favored theories of giant planet formation center around two main paradigms, namely the core accretion model and the gravitational instability model. These two formation scenarios support the hypothesis that the giant planet metallicities should be higher or equal to that of the parent star. Meanwhile, spectra of the transiting hot Jupiter HD189733b suggest that carbon and oxygen abundances range from depleted to enriched with respect to the star. Here, using a model describing the formation sequence and composition of planetesimals in the protoplanetary disk, we determine the range of volatile abundances in the envelope of HD189733b that is consistent with the 20--80 Earth-masses of heavy elements estimated to be present in the planet's envelope. We then compare the inferred carbon and oxygen abundances to those retrieved from spectroscopy and we find a range of supersolar values that directly fit both spectra and internal structure models. In some cases, we find that the apparent contradiction between the subsolar elemental abundances and the {mass of heavy elements predicted in HD189733b by internal structure models} can be explained by the presence of large amounts of carbon molecules in the form of polycyclic aromatic hydrocarbons and soots in the upper layers of the envelope, as suggested by recent photochemical models. A diagnostic test that would confirm the presence of these compounds in the envelope is the detection of acetylene., Accepted for publication in The Astrophysical Journal
Published: 2011
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20. On the stability of clathrate hydrates in comets 67P/Churyumov-Gerasimenko and 46P/Wirtanen

Author: Bernard Schmitt, J. M. Petit, Olivier Mousis, Harold A. Weaver, Anita L. Cochran, Ulysse Marboeuf, Laboratoire de Planétologie de Grenoble (LPG), Université Joseph Fourier - Grenoble 1 (UJF)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Univers, Transport, Interfaces, Nanostructures, Atmosphère et environnement, Molécules (UMR 6213) (UTINAM), Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université de Franche-Comté (UFC), Université Bourgogne Franche-Comté [COMUE] (UBFC)-Université Bourgogne Franche-Comté [COMUE] (UBFC), McDonald Observatory, University of Texas at Austin [Austin], Johns Hopkins University Applied Physics Laboratory [Laurel, MD] (APL), Université de Franche-Comté (UFC), Université Bourgogne Franche-Comté [COMUE] (UBFC)-Université Bourgogne Franche-Comté [COMUE] (UBFC)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS), Institut de Planétologie et d'Astrophysique de Grenoble (IPAG ), Observatoire des Sciences de l'Univers de Grenoble (OSUG), Université Joseph Fourier - Grenoble 1 (UJF)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Institut national des sciences de l'Univers (INSU - CNRS)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Université Joseph Fourier - Grenoble 1 (UJF)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Institut national des sciences de l'Univers (INSU - CNRS)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS), Institut UTINAM (Univers, transport, interfaces, nanostructures, atmosphère et environnement, molécules) (Besançon), Institut de Planétologie et d'Astrophysique de Grenoble (IPAG), Centre National d'Études Spatiales [Toulouse] (CNES)-Université Grenoble Alpes (UGA)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire des Sciences de l'Univers de Grenoble (OSUG), and Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Joseph Fourier - Grenoble 1 (UJF)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes (UGA)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Joseph Fourier - Grenoble 1 (UJF)-Centre National de la Recherche Scientifique (CNRS)
Subjects: Phase transition, 010504 meteorology & atmospheric sciences, [PHYS.ASTR.EP]Physics [physics]/Astrophysics [astro-ph]/Earth and Planetary Astrophysics [astro-ph.EP], Comet, Clathrate hydrate, Astrophysics, 01 natural sciences, Astrobiology, 0103 physical sciences, 010303 astronomy & astrophysics, ComputingMilieux_MISCELLANEOUS, 0105 earth and related environmental sciences, Physics, Spacecraft, business.industry, comets: general, comets: individual: 67P/Churyumov-Gerasimenko, Astronomy and Astrophysics, Amorphous solid, 13. Climate action, Space and Planetary Science, Amorphous ice, SPHERES, Sublimation (phase transition), comets: individual: 46P/Wirtanen, business, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph]
Abstract: International audience; Context. For several years, Jupiter-family comets have been the targets of spacecraft missions whose aims are to determine the comets' composition, structure, and physical properties. The Rosetta mission is currently flying towards comet 67P/Churyumov Gerasimenko for a rendezvous in August 2014 and comet 46P/Wirtanen is considered for a rendezvous in 2021 with the PriME (Primitive Material Explorer) mission, which is currently proposed to NASA.Aims: Here we investigate the stability conditions of clathrate hydrates within the comets 67P/Churyumov-Gerasimenko and 46P/Wirtanen by considering an initial mixture of amorphous H2O with CO, CO2, CH4, and H2S in the nuclei.Methods: We use a one-dimensional nucleus model, which considers an initially homogeneous sphere composed of a predefined porous mixture of ices and dust in specified proportions and describes heat transmission, gas diffusion, sublimation/recondensation of volatiles within the nucleus, water ice phase transition, dust release, and mantle formation.Results: We show that stability conditions of multiple guest clathrates are permanently reached in the subsurface of both comets, and in a broader manner in the subsurface of all short period comets. The thickness of the stability zone of the clathrate slightly oscillates with time as a function of the heliocentric distance, but never vanishes. When comets approach perihelion, our calculations suggest that clathrate layers, which are located closer to the nucleus surface, may destabilize before amorphous ice is tranformed into crystalline ice.
Published: 2011
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21. Constraints on the Volatile Enrichments in HD189733b from Internal Structure Models

Author: Olivier Mousis, Lunine, J., Zahnie, K., Ludovic Biennier, Sylvain Picaud, Johnson, T. V., Jean-Marc Petit, Brian Mitchell, Ph Beaulieu, J., Vincent Boudon, Daniel Cordier, Devel, M., Robert Georges, Griffith, Caitlin A., Nicolas Iro, Marley, M. S., Ulysse Marboeuf, Giovanna Tinetti, Univers, Transport, Interfaces, Nanostructures, Atmosphère et environnement, Molécules (UMR 6213) (UTINAM), Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université de Franche-Comté (UFC), Université Bourgogne Franche-Comté [COMUE] (UBFC)-Université Bourgogne Franche-Comté [COMUE] (UBFC), Laboratoire de Physique Moléculaire (UMR 6624) (LPM), Centre National de la Recherche Scientifique (CNRS)-Université de Franche-Comté (UFC), Laboratoire Interdisciplinaire Carnot de Bourgogne (ICB), Université de Bourgogne (UB)-Centre National de la Recherche Scientifique (CNRS), Institut de Physique de Rennes (IPR), Université de Rennes (UR)-Centre National de la Recherche Scientifique (CNRS), Ecole Nationale Supérieure de Chimie de Rennes (ENSCR), Franche-Comté Électronique Mécanique, Thermique et Optique - Sciences et Technologies (UMR 6174) (FEMTO-ST), Université de Technologie de Belfort-Montbeliard (UTBM)-Ecole Nationale Supérieure de Mécanique et des Microtechniques (ENSMM)-Centre National de la Recherche Scientifique (CNRS)-Université de Franche-Comté (UFC), Lunar and Planetary Laboratory [Tucson] (LPL), University of Arizona, University College of London [London] (UCL), Université de Franche-Comté (UFC), Université Bourgogne Franche-Comté [COMUE] (UBFC)-Université Bourgogne Franche-Comté [COMUE] (UBFC)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS), Université Bourgogne Franche-Comté [COMUE] (UBFC)-Université Bourgogne Franche-Comté [COMUE] (UBFC)-Centre National de la Recherche Scientifique (CNRS), Laboratoire Interdisciplinaire Carnot de Bourgogne (LICB), Université de Rennes 1 (UR1), Université de Rennes (UNIV-RENNES)-Université de Rennes (UNIV-RENNES)-Centre National de la Recherche Scientifique (CNRS), Université de Technologie de Belfort-Montbeliard (UTBM)-Ecole Nationale Supérieure de Mécanique et des Microtechniques (ENSMM)-Université de Franche-Comté (UFC), Univers, Transport, Interfaces, Nanostructures, Atmosphère et environnement, Molécules ( UTINAM ), Institut national des sciences de l'Univers ( INSU - CNRS ) -Centre National de la Recherche Scientifique ( CNRS ) -Université de Franche-Comté ( UFC ), Laboratoire de Physique Moléculaire ( LPM ), Centre National de la Recherche Scientifique ( CNRS ) -Université de Franche-Comté ( UFC ), Laboratoire Interdisciplinaire Carnot de Bourgogne ( LICB ), Université de Bourgogne ( UB ) -Centre National de la Recherche Scientifique ( CNRS ), Institut de Physique de Rennes ( IPR ), Université de Rennes 1 ( UR1 ), Université de Rennes ( UNIV-RENNES ) -Université de Rennes ( UNIV-RENNES ) -Centre National de la Recherche Scientifique ( CNRS ), Ecole Nationale Supérieure de Chimie de Rennes, Franche-Comté Électronique Mécanique, Thermique et Optique - Sciences et Technologies ( FEMTO-ST ), Université de Technologie de Belfort-Montbeliard ( UTBM ) -Ecole Nationale Supérieure de Mécanique et des Microtechniques ( ENSMM ) -Centre National de la Recherche Scientifique ( CNRS ) -Université de Franche-Comté ( UFC ), Lunar and Planetary Laboratory [Tucson], University College of London [London] ( UCL ), and Boudon, Vincent
Subjects: [CHIM.THEO]Chemical Sciences/Theoretical and/or physical chemistry, [CHIM.THEO] Chemical Sciences/Theoretical and/or physical chemistry, [ CHIM.THEO ] Chemical Sciences/Theoretical and/or physical chemistry, ComputingMilieux_MISCELLANEOUS
Abstract: International audience
Published: 2010

22. CLATHRATE HYDRATES FORMATION IN SHORT-PERIOD COMETS

Author: Bernard Schmitt, Ulysse Marboeuf, Olivier Mousis, Jean-Marc Petit, Laboratoire d'astrophysique de l'observatoire de Besançon (UMR 6091) (LAOB), Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université de Franche-Comté (UFC), Université Bourgogne Franche-Comté [COMUE] (UBFC)-Université Bourgogne Franche-Comté [COMUE] (UBFC), Univers, Transport, Interfaces, Nanostructures, Atmosphère et environnement, Molécules (UMR 6213) (UTINAM), Université de Franche-Comté (UFC), Université Bourgogne Franche-Comté [COMUE] (UBFC)-Université Bourgogne Franche-Comté [COMUE] (UBFC)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS), Institut de Planétologie et d'Astrophysique de Grenoble (IPAG ), Observatoire des Sciences de l'Univers de Grenoble (OSUG), Université Joseph Fourier - Grenoble 1 (UJF)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Institut national des sciences de l'Univers (INSU - CNRS)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Université Joseph Fourier - Grenoble 1 (UJF)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Institut national des sciences de l'Univers (INSU - CNRS)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS), Laboratoire d'astrophysique de l'observatoire de Besançon (LAOB), Institut UTINAM (Univers, transport, interfaces, nanostructures, atmosphère et environnement, molécules) (Besançon), Institut de Planétologie et d'Astrophysique de Grenoble (IPAG), Centre National d'Études Spatiales [Toulouse] (CNES)-Université Grenoble Alpes (UGA)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire des Sciences de l'Univers de Grenoble (OSUG), and Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Joseph Fourier - Grenoble 1 (UJF)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes (UGA)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Joseph Fourier - Grenoble 1 (UJF)-Centre National de la Recherche Scientifique (CNRS)
Subjects: Physics, Carbon dioxide clathrate, 010308 nuclear & particles physics, [PHYS.ASTR.EP]Physics [physics]/Astrophysics [astro-ph]/Earth and Planetary Astrophysics [astro-ph.EP], Clathrate hydrate, Comet, Astronomy and Astrophysics, 01 natural sciences, Astrobiology, Jupiter, 13. Climate action, Space and Planetary Science, Planet, 0103 physical sciences, Amorphous ice, Gas composition, 010303 astronomy & astrophysics, Order of magnitude, ComputingMilieux_MISCELLANEOUS
Abstract: The initial composition of current models of cometary nuclei is only based on two forms of ice: crystalline ice for long-period comets and amorphous ice for short-period comets. A third form of ice, i.e., clathrate hydrate, could exist within the short-period cometary nuclei, but the area of formation of this crystalline structure in these objects has never been studied. Here, we show that the thermodynamic conditions in the interior of short-period comets allow the existence of clathrate hydrates in Halley-type comets. We show that their existence is viable in the Jupiter family comets only when the equilibrium pressure of CO clathrate hydrate is at least 1 order of magnitude lower than the usually assumed theoretical value. We calculate that the amount of volatiles that could be trapped in the clathrate hydrate layer may be orders of magnitude greater than the daily amount of gas released at the surface of the nucleus at perihelion. The formation and the destruction of the clathrate hydrate cages could then explain the diversity of composition of volatiles observed in comets, as well as some pre-perihelion outbursts. We finally show that the potential clathrate hydrate layer in comet 67P/Churyumov-Gerasimenko would, unfortunately, be deep inside the nucleus, out of reach of the Rosetta lander. However, such a clathrate hydrate layer would show up by the gas composition of the coma.
Published: 2010
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23. Can collisional activity produce a crystallization of Edgeworth-Kuiper Belt comets?

Author: Olivier Mousis, Ulysse Marboeuf, Jean-Marc Petit, Laboratoire d'astrophysique de l'observatoire de Besançon (UMR 6091) (LAOB), Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université de Franche-Comté (UFC), Université Bourgogne Franche-Comté [COMUE] (UBFC)-Université Bourgogne Franche-Comté [COMUE] (UBFC), Univers, Transport, Interfaces, Nanostructures, Atmosphère et environnement, Molécules (UMR 6213) (UTINAM), Université de Franche-Comté (UFC), and Université Bourgogne Franche-Comté [COMUE] (UBFC)-Université Bourgogne Franche-Comté [COMUE] (UBFC)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)
Subjects: Physics, Planetesimal, Solar System, 010504 meteorology & atmospheric sciences, [PHYS.ASTR.EP]Physics [physics]/Astrophysics [astro-ph]/Earth and Planetary Astrophysics [astro-ph.EP], Astronomy and Astrophysics, Astrophysics, 01 natural sciences, Amorphous solid, Astrobiology, law.invention, 13. Climate action, Space and Planetary Science, law, Continuous crystallization, 0103 physical sciences, Amorphous ice, Crystallization, Formation and evolution of the Solar System, 010303 astronomy & astrophysics, ComputingMilieux_MISCELLANEOUS, 0105 earth and related environmental sciences
Abstract: Kuiper Belt Objects and cometary nuclei are considered among the most pristine bodies of the outer Solar system. However, the composition of these objects might not reflect that of the planetesimals from which they accreted. They have experienced some collisional activity since the formation of the Edgeworth–Kuiper Belt, leading to a possible alteration of their structure and composition. Here, we examine the possible alteration of icy bodies (10 to 100 km radii) located in the primitive Edgeworth–Kuiper Belt due to the heat generated by collisions of planetesimals with sizes not exceeding 10 per cent of the target body. We use a cometary nucleus model initially made of a mixture of amorphous ice and dust to investigate the influence of the target’s intrinsic properties on its post-impact thermodynamical evolution. We show that multiple collisions must be considered over long periods to trigger a continuous crystallization within a target owning a typical cometary composition. However, the collision rates we have determined are approximately 1000 times greater than those predicted for the current collisional environment in the Edgeworth–Kuiper Belt. This implies that the collisional processes that occurred over the age of the Solar system did not produce any phase transition of H2O ice from amorphous to crystalline forms in cometary size bodies located in the primitive Edgeworth–Kuiper Belt.
Published: 2009
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24. Determination of the minimum masses of heavy elements in the envelopes of Jupiter and Saturn

Author: Yves Ellinger, Françoise Pauzat, Jonathan I. Lunine, Ulysse Marboeuf, Yann Alibert, Glenn S. Orton, Olivier Mousis, Leigh N. Fletcher, Univers, Transport, Interfaces, Nanostructures, Atmosphère et environnement, Molécules (UMR 6213) (UTINAM), Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université de Franche-Comté (UFC), Université Bourgogne Franche-Comté [COMUE] (UBFC)-Université Bourgogne Franche-Comté [COMUE] (UBFC), Lunar and Planetary Laboratory [Tucson] (LPL), University of Arizona, Jet Propulsion Laboratory (JPL), NASA-California Institute of Technology (CALTECH), Laboratoire de chimie théorique (LCT), and Institut de Chimie du CNRS (INC)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)
Subjects: Planetesimal, 010504 meteorology & atmospheric sciences, Hydrogen, [PHYS.ASTR.EP]Physics [physics]/Astrophysics [astro-ph]/Earth and Planetary Astrophysics [astro-ph.EP], chemistry.chemical_element, FOS: Physical sciences, Astrophysics, 01 natural sciences, 7. Clean energy, Jupiter, Saturn, 0103 physical sciences, Astrophysics::Solar and Stellar Astrophysics, 010303 astronomy & astrophysics, Refractory (planetary science), ComputingMilieux_MISCELLANEOUS, Astrophysics::Galaxy Astrophysics, 0105 earth and related environmental sciences, Physics, Nebula, Astrophysics (astro-ph), Astronomy and Astrophysics, chemistry, 13. Climate action, Space and Planetary Science, Physics::Space Physics, Great conjunction, Astrophysics::Earth and Planetary Astrophysics, Formation and evolution of the Solar System
Abstract: We calculate the minimum mass of heavy elements required in the envelopes of Jupiter and Saturn to match the observed oversolar abundances of volatiles. Because the clathration efficiency remains unknown in the solar nebula, we have considered a set of sequences of ice formation in which the fraction of water available for clathration is varied between 0 and 100 %. In all the cases considered, we assume that the water abundance remains homogeneous whatever the heliocentric distance in the nebula and directly derives from a gas phase of solar composition. Planetesimals then form in the feeding zones of Jupiter and Saturn from the agglomeration of clathrates and pure condensates in proportions fixed by the clathration efficiency. A fraction of Kr and Xe may have been sequestrated by the H3+ ion in the form of stable XeH3+ and KrH3+ complexes in the solar nebula gas phase, thus implying the formation of at least partly Xe- and Kr-impoverished planetesimals in the feeding zones of Jupiter and Saturn. These planetesimals were subsequently accreted and vaporized into the hydrogen envelopes of Jupiter and Saturn, thus engendering volatiles enrichments in their atmospheres, with respect to hydrogen. Taking into account both refractory and volatile components, and assuming plausible molecular mixing ratios in the gas phase of the outer solar nebula, we show that it is possible to match the observed enrichments in Jupiter and Saturn, whatever the clathration efficiency. Our calculations predict that the O/H enrichment decreases from 6.7 to 5.6 times solar (O/H) in the envelope of Jupiter and from 18.1 to 15.4 times solar (O/H) in the envelope of Saturn with the growing clathration efficiency in the solar nebula., Comment: Accepted for publication in The Astrophysical Journal
Published: 2008
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25. Composition of Ices in Low-Mass Extrasolar Planets

Author: Arnaud Cassan, Jean-Philippe Beaulieu, O. Mousis, Valentine Wakelam, Ulysse Marboeuf, David Ehrenreich, Yann Alibert, Laboratoire d'astrophysique de l'observatoire de Besançon (UMR 6091) (LAOB), Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université de Franche-Comté (UFC), Université Bourgogne Franche-Comté [COMUE] (UBFC)-Université Bourgogne Franche-Comté [COMUE] (UBFC), Institut d'Astrophysique de Paris (IAP), Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC), Laboratoire d'Astrophysique de Grenoble (LAOG), Université Joseph Fourier - Grenoble 1 (UJF)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Centre de Recherche Astrophysique de Lyon (CRAL), École normale supérieure - Lyon (ENS Lyon)-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS), Astronomische Rechen-Institut [Heidelberg] (ARI), Zentrum für Astronomie der Universität Heidelberg (ZAH), Universität Heidelberg [Heidelberg]-Universität Heidelberg [Heidelberg], Laboratoire d'astrodynamique, d'astrophysique et d'aéronomie de bordeaux (L3AB), Université Sciences et Technologies - Bordeaux 1-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Observatoire aquitain des sciences de l'univers (OASU), Laboratoire d'Astrophysique de Bordeaux [Pessac] (LAB), Université de Bordeaux (UB)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Department of Physics, Ohio State University [Columbus] (OSU), Department of Physics, The Ohio State University, Department of Physics (OSU), Natural Resources Canada (NRCan), Institut Méditerranéen d'Ecologie et de Paléoécologie (IMEP), Université Paul Cézanne - Aix-Marseille 3-Centre National de la Recherche Scientifique (CNRS)-Avignon Université (AU)-Université de Provence - Aix-Marseille 1, Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Université Sciences et Technologies - Bordeaux 1 (UB)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), École normale supérieure de Lyon (ENS de Lyon)-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Universität Heidelberg [Heidelberg] = Heidelberg University-Universität Heidelberg [Heidelberg] = Heidelberg University, and Université Paul Cézanne - Aix-Marseille 3-Université de Provence - Aix-Marseille 1-Avignon Université (AU)-Centre National de la Recherche Scientifique (CNRS)
Subjects: Planetesimal, 010504 meteorology & atmospheric sciences, Stars: Planetary Systems, [PHYS.ASTR.EP]Physics [physics]/Astrophysics [astro-ph]/Earth and Planetary Astrophysics [astro-ph.EP], [SDU.ASTR.EP]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Earth and Planetary Astrophysics [astro-ph.EP], chemistry.chemical_element, FOS: Physical sciences, Astrophysics, Gravitational microlensing, 01 natural sciences, [PHYS.ASTR.CO]Physics [physics]/Astrophysics [astro-ph]/Cosmology and Extra-Galactic Astrophysics [astro-ph.CO], Planet, 0103 physical sciences, 14. Life underwater, 010303 astronomy & astrophysics, 0105 earth and related environmental sciences, Physics, [SDU.ASTR]Sciences of the Universe [physics]/Astrophysics [astro-ph], Astrophysics (astro-ph), Astronomy and Astrophysics, Planetary system, Exoplanet, chemistry, 13. Climate action, Space and Planetary Science, Stars: Planetary Systems: Formation, Astrophysics::Earth and Planetary Astrophysics, Low Mass, Carbon, Mass fraction
Abstract: We study the formation conditions of icy planetesimals in protoplanetary disks in order to determine the composition of ices in small and cold extrasolar planets. Assuming that ices are formed from hydrates, clathrates, and pure condensates, we calculate their mass fractions with respect to the total quantity of ices included in planetesimals, for a grid of disk models. We find that the composition of ices weakly depends on the adopted disk thermodynamic conditions, and is rather influenced by the initial composition of the gas phase. The use of a plausible range of molecular abundance ratios and the variation of the relative elemental carbon over oxygen ratio in the gas phase of protoplanetary disks, allow us to apply our model to a wide range of planetary systems. Our results can thus be used to constrain the icy/volatile phase composition of cold planets evidenced by microlensing surveys, hypothetical ocean-planets and carbon planets, which could be detected by Corot or Kepler., Comment: Accepted for publication in The Astrophysical Journal
Published: 2008
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26. Expectations for the Deep Impact collision from modelling of cometary nuclei

Author: Jean-Marc Petit, Ulysse Marboeuf, Jurgen Klinger, O. Mousis, Univers, Transport, Interfaces, Nanostructures, Atmosphère et environnement, Molécules (UMR 6213) (UTINAM), Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université de Franche-Comté (UFC), Laboratoire de Planétologie de Grenoble (LPG), Université Joseph Fourier - Grenoble 1 (UJF)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Institut UTINAM (Univers, transport, interfaces, nanostructures, atmosphère et environnement, molécules) (Besançon), Laboratoire de glaciologie et géophysique de l'environnement (LGGE), Observatoire des Sciences de l'Univers de Grenoble (OSUG), Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Joseph Fourier - Grenoble 1 (UJF)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes (UGA)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Joseph Fourier - Grenoble 1 (UJF)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes (UGA)-Centre National de la Recherche Scientifique (CNRS), Université de Franche-Comté (UFC)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS), Université de Franche-Comté (UFC), Université Bourgogne Franche-Comté [COMUE] (UBFC)-Université Bourgogne Franche-Comté [COMUE] (UBFC)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS), Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire des Sciences de l'Univers de Grenoble (OSUG), Université Joseph Fourier - Grenoble 1 (UJF)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Institut national des sciences de l'Univers (INSU - CNRS)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Université Joseph Fourier - Grenoble 1 (UJF)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS), Laboratoire d'astrophysique de l'observatoire de Besançon (UMR 6091) (LAOB), and Université Bourgogne Franche-Comté [COMUE] (UBFC)-Université Bourgogne Franche-Comté [COMUE] (UBFC)
Subjects: Physics, 010504 meteorology & atmospheric sciences, Projectile, [PHYS.ASTR.EP]Physics [physics]/Astrophysics [astro-ph]/Earth and Planetary Astrophysics [astro-ph.EP], Comet, Astronomy and Astrophysics, Astrophysics, Collision, 01 natural sciences, Amorphous solid, Astrobiology, [PHYS.ASTR.CO]Physics [physics]/Astrophysics [astro-ph]/Cosmology and Extra-Galactic Astrophysics [astro-ph.CO], medicine.anatomical_structure, Impact crater, Orders of magnitude (time), 13. Climate action, Space and Planetary Science, 0103 physical sciences, medicine, 010303 astronomy & astrophysics, Nucleus, ComputingMilieux_MISCELLANEOUS, 0105 earth and related environmental sciences, Production rate
Abstract: Using the cometary nucleus model developed by Espinasse et al., we calculate the thermodynamical evolution of Comet 9P/Tempel 1 over a period of 360 yr. Starting from an initially amorphous cometary nucleus which incorporates an icy mixture of H2O and CO, we show that, at the time of Deep Impact collision, the crater is expected to form at depths where ice is in its crystalline form. Hence the subsurface exposed to space should not be primordial. We also attempt an order-of-magnitude estimate of the heating and material ablation effects on the crater activity caused by the 370-kg projectile released by the Deep Impact spacecraft. We thus show that heating effects play no role in the evolution of crater activity. We calculate that the CO production rate from the impacted region should be about 300‐400 times higher from the crater resulting from the impact with a 35-m ablation than over the unperturbed nucleus in the immediate post-impact period. We also show that the H2O production rate is decreased by several orders of magnitude at the crater base just after ablation. Ke yw ords: comets: individual: 9P/Tempel 1.
Published: 2005
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27. From planetesimals to planets: volatile molecules

Author: Amaury Thiabaud, Nahuel Cabral, Willy Benz, Ulysse Marboeuf, Yann Alibert, Universität Bern [Bern], Univers, Transport, Interfaces, Nanostructures, Atmosphère et environnement, Molécules (UMR 6213) (UTINAM), Université de Franche-Comté (UFC), and Université Bourgogne Franche-Comté [COMUE] (UBFC)-Université Bourgogne Franche-Comté [COMUE] (UBFC)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)
Subjects: Earth and Planetary Astrophysics (astro-ph.EP), Physics, Nebula, Planetesimal, 530 Physics, Gas giant, FOS: Physical sciences, Astronomy and Astrophysics, Exoplanet, Astrobiology, Atmosphere, 13. Climate action, Space and Planetary Science, Planet, Astrophysics::Solar and Stellar Astrophysics, Terrestrial planet, Astrophysics::Earth and Planetary Astrophysics, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], Chemical composition, Astrophysics::Galaxy Astrophysics, ComputingMilieux_MISCELLANEOUS, Astrophysics - Earth and Planetary Astrophysics
Abstract: Context. Solar and extrasolar planets are the subject of numerous studies aiming to determine their chemical composition and internal structure. In the case of extrasolar planets, the composition is important as it partly governs their potential habitability. Moreover, observational determination of chemical composition of planetary atmospheres are becoming available, especially for transiting planets. Aims. The present works aims at determining the chemical composition of planets formed in stellar systems of solar chemical composition. The main objective of this work is to provide valuable theoretical data for models of planet formation and evolution, and future interpretation of chemical composition of solar and extrasolar planets. Methods. We have developed a model that computes the composition of ices in planets in different stellar systems with the use of models of ice and planetary formation. Results. We provide the chemical composition, ice/rock mass ratio and C:O molar ratio for planets in stellar systems of solar chemical composition. From an initial homogeneous composition of the nebula, we produce a wide variety of planetary chemical compositions as a function of the mass of the disk and distance to the star. The volatile species incorporated in planets are mainly composed of H2O, CO, CO2, CH3OH, and NH3. Icy or ocean planets have systematically higher values of molecular abundances compared to giant and rocky planets. Gas giant planets are depleted in highly volatile molecules such as CH4, CO, and N2 compared to icy or ocean planets. The ice/rock mass ratio in icy or ocean and gas giant planets is, respectively, equal at maximum to 1.01 ± 0.33 and 0.8 ± 0.5, and is different from the usual assumptions made in planet formation models, which suggested this ratio to be 2–3. The C:O molar ratio in the atmosphere of gas giant planets is depleted by at least 30% compared to solar value.
Published: 2014
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28. A SEARCH FOR WATER VAPORIZATION ON CERES

Author: Olivier Mousis, Emmanuel Jehin, Benoit Carry, Christophe Dumas, J.-M. Zucconi, Philippe Rousselot, Ulysse Marboeuf, and Jean Manfroid
Subjects: Physics, Very Large Telescope, Solar System, Space and Planetary Science, Planet, Asteroid, Dwarf planet, Astronomy, Flux, Astronomy and Astrophysics, Regolith, Spectral line
Abstract: There are hints that the dwarf planet (1) Ceres may contain a large amount of water ice. Some models and previous observations suggest that ice could be close enough to the surface to create a flux of water outward through the regolith. This work aims to confirm a previous detection of OH emission off the northern limb of Ceres with the International Ultraviolet Explorer (IUE). Such emission would be evidence of water molecules escaping from the dwarf planet. We used the Ultraviolet and Visual Echelle Spectrograph of the Very Large Telescope to obtain spectra off the northern and southern limbs of Ceres at several epochs. These spectra cover the 307-312 nm wavelength range corresponding to the OH (0,0) emission band, which is the brightest band of this radical, well known in the cometary spectra. These new observations, five times more sensitive than those from IUE, did not permit detection of OH around Ceres. We derive an upper limit for the water production of about {approx}7 x 10{sup 25} molecules s{sup -1} and estimate the minimum thickness of the dust surface layer above the water ice layer (if present) to be about 20 m.
Published: 2011
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28 results on '"Ulysse Marboeuf"'

1. Gas composition of main volatile elements in protoplanetary discs and its implication for planet formation

2. Isotopic ratios D/H and 15N/14N in giant planets

3. Radial Drift and Concurrent Ablation of Boulder-Sized Objects

4. Laboratory Studies Towards Understanding Comets

5. Laboratory Studies Towards Understanding Comets

6. How to link the relative abundances of gas species in coma of comets to their initial chemical composition?

7. Cometary ices in forming protoplanetary disc midplanes

8. Subsurface characterization of 67P/Churyumov-Gerasimenko's abydos site

9. Equilibrium Pressure of Ethane, Acetylene, and Krypton Clathrate Hydrates below the Freezing Point of Water

10. Hydrogen sulfide clathrate hydrate FTIR spectroscopy: A help gas for clathrate formation in the Solar System?

11. Pressure dependent trace gas trapping in amorphous water ice at 77 K: Implications for determining conditions of comet formation

12. Equilibrium Data of Methane, Carbon Dioxide, and Xenon Clathrate Hydrates below the Freezing Point of Water. Applications to Astrophysical Environments

13. Origin of volatiles in the main belt

14. Elemental ratios in stars vs planets

15. Kinetics of hydrogen/deuterium exchanges in cometary ices

16. Gas composition of main volatile elements in protoplanetary discs and its implication for planet formation

17. From stellar nebula to planets: the refractory components

18. A cometary nucleus model taking into account all phase changes of water ice: amorphous, crystalline, and clathrate

19. On the Volatile Enrichments and Heavy Element Content in HD 189733b

20. On the stability of clathrate hydrates in comets 67P/Churyumov-Gerasimenko and 46P/Wirtanen

21. Constraints on the Volatile Enrichments in HD189733b from Internal Structure Models

22. CLATHRATE HYDRATES FORMATION IN SHORT-PERIOD COMETS

23. Can collisional activity produce a crystallization of Edgeworth-Kuiper Belt comets?

24. Determination of the minimum masses of heavy elements in the envelopes of Jupiter and Saturn

25. Composition of Ices in Low-Mass Extrasolar Planets

26. Expectations for the Deep Impact collision from modelling of cometary nuclei

27. From planetesimals to planets: volatile molecules

28. A SEARCH FOR WATER VAPORIZATION ON CERES

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28 results on '"Ulysse Marboeuf"'

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