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32 results on '"Ellinger, Y."'

1. Stability of sulphur dimers S2 in cometary ices

Author

Mousis, O., Ozgurel, O., Lunine, J. I., Luspay-Kuti, A., Ronnet, T., Pauzat, F., Markovits, A., and Ellinger, Y.

Subjects
Astrophysics - Earth and Planetary Astrophysics
Abstract

S2 has been observed for decades in comets, including comet 67P/Churyumov-Gerasimenko. Despite the fact that this molecule appears ubiquitous in these bodies, the nature of its source remains unknown. In this study, we assume that S2 is formed by irradiation (photolysis and/or radiolysis) of S-bearing molecules embedded in the icy grain precursors of comets, and that the cosmic ray flux simultaneously creates voids in ices within which the produced molecules can accumulate. We investigate the stability of S2 molecules in such cavities, assuming that the surrounding ice is made of H2S or H2O. We show that the stabilization energy of S2 molecules in such voids is close to that of the H2O ice binding energy, implying that they can only leave the icy matrix when this latter sublimates. Because S2 has a short lifetime in the vapor phase, we derive that its formation in grains via irradiation must occur only in low density environments such as the ISM or the upper layers of the protosolar nebula, where the local temperature is extremely low. In the first case, comets would have agglomerated from icy grains that remained pristine when entering the nebula. In the second case, comets would have agglomerated from icy grains condensed in the protosolar nebula and that would have been efficiently irradiated during their turbulent transport towards the upper layers of the disk. Both scenarios are found consistent with the presence of molecular oxygen in comets., Comment: Accepted for publication in The Astrophysical Journal

Published
2016
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2. Origin of molecular oxygen in Comet 67P/Churyumov-Gerasimenko

Author

Mousis, O., Ronnet, T., Brugger, B., Ozgurel, O., Pauzat, F., Ellinger, Y., Maggiolo, R., Wurz, P., Vernazza, P., Lunine, J. I., Luspay-Kuti, A., Mandt, K. E., Altwegg, K., Bieler, A., Markovits, A., and Rubin, M.

Subjects
Astrophysics - Earth and Planetary Astrophysics
Abstract

Molecular oxygen has been detected in the coma of comet 67P/Churyumov-Gerasimenko with abundances in the 1-10% range by the ROSINA-DFMS instrument on board the Rosetta spacecraft. Here we find that the radiolysis of icy grains in low-density environments such as the presolar cloud may induce the production of large amounts of molecular oxygen. We also show that molecular oxygen can be efficiently trapped in clathrates formed in the protosolar nebula, and that its incorporation as crystalline ice is highly implausible because this would imply much larger abundances of Ar and N2 than those observed in the coma. Assuming that radiolysis has been the only O2 production mechanism at work, we conclude that the formation of comet 67P/Churyumov-Gerasimenko is possible in a dense and early protosolar nebula in the framework of two extreme scenarios: (1) agglomeration from pristine amorphous icy grains/particles formed in ISM and (2) agglomeration from clathrates that formed during the disk's cooling. The former scenario is found consistent with the strong correlation between O2 and H2O observed in 67P/C-G's coma while the latter scenario requires that clathrates formed from ISM icy grains that crystallized when entering the protosolar nebula., Comment: The Astrophysical Journal Letters, in press

Published
2016
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3. The composition of the protosolar disk and the formation conditions for comets

Author

Willacy, K., Alexander, C., Ali-Dib, M., Ceccarelli, C., Charnley, S. B., Doronin, M., Ellinger, Y., Gast, P., Gibb, E., Milam, S. N., Mousis, O., Pauzat, E., Tornow, C., Wirstrom, E. S., and Zicler, E

Subjects
Astrophysics - Earth and Planetary Astrophysics
Abstract

Conditions in the protosolar nebula have left their mark in the composition of cometary volatiles, thought to be some of the most pristine material in the solar system. Cometary compositions represent the end point of processing that began in the parent molecular cloud core and continued through the collapse of that core to form the protosun and the solar nebula, and finally during the evolution of the solar nebula itself as the cometary bodies were accreting. Disentangling the effects of the various epochs on the final composition of a comet is complicated. But comets are not the only source of information about the solar nebula. Protostellar disks around young stars similar to the protosun provide a way of investigating the evolution of disks similar to the solar nebula while they are in the process of evolving to form their own solar systems. In this way we can learn about the physical and chemical conditions under which comets formed, and about the types of dynamical processing that shaped the solar system we see today. This paper summarizes some recent contributions to our understanding of both cometary volatiles and the composition, structure and evolution of protostellar disks., Comment: To appear in Space Science Reviews. The final publication is available at Springer via http://dx.doi.org/10.1007/s11214-015-0167-6

Published
2015
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4. Adsorption of atomic hydrogen as driving vector for solid-gas processes on ices

Author

Tieppo, N, Pauzat, F, Parisel, O, Ellinger, Y, Laboratoire de chimie théorique (LCT), Institut de Chimie du CNRS (INC)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Institut des Sciences Chimiques de Rennes (ISCR), Université de Rennes (UR)-Institut National des Sciences Appliquées - Rennes (INSA Rennes), and 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)

Subjects
molecular processes, [SDU.ASTR]Sciences of the Universe [physics]/Astrophysics [astro-ph], astrochemistry, Space and Planetary Science, [CHIM]Chemical Sciences, Astronomy and Astrophysics, ISM: abundances, ISM: molecules
Abstract

A consensus has progressively developed that the path towards complex organic molecules could be favoured by the icy mantles of interstellar dust particles. However, the question of whether activation energy is required to promote those reactions is open. This work deals with the simplest process thought to increase complexity i.e. successive additions of a single atom (H). Two situations can be considered, the direct additions of H in the gas phase and the atomic hydrogenation processes on water ice surfaces available in the interstellar medium (ISM). The synthesis of methanol, largely discussed in the literature is revisited as a case study. Computational investigations of the reactions leading from CO to CH3OH show that, with [H...(H2O)n] complexes as hydrogenation vectors, all steps of the process are barrier-less, contrary to the gas phase process and this, whatever the level of theory considered. The key parameter is the position of the CO + [H...(H2O)n] initial system on the global energy scale. At the present level of theory, when H is pre-adsorbed on the ice, the system happens to be high enough above the reaction path, namely, above any intermediates and possible transition states. This is true whatever the dimension of the ice support, even for the simplest model of one H2O molecule. Application of such a simplified synthetic approach, here validated for the synthesis of methanol, could be generalized, providing a simple way to get a fair insight into the important class of atomic hydrogenations on ices in the ISM.

Published
2022
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5. The Composition of the Protosolar Disk and the Formation Conditions for Comets

Author

Willacy, K., primary, Alexander, C., additional, Ali-Dib, M., additional, Ceccarelli, C., additional, Charnley, S. B., additional, Doronin, M., additional, Ellinger, Y., additional, Gast, P., additional, Gibb, E., additional, Milam, S. N., additional, Mousis, O., additional, Pauzat, F., additional, Tornow, C., additional, Wirström, E. S., additional, and Zicler, E., additional

Published
2017
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6. Adsorption of atomic hydrogen as driving vector for solid-gas processes on ices.

Author

Tieppo, N, Pauzat, F, Parisel, O, and Ellinger, Y

Subjects
ATOMIC hydrogen, TRANSITION state theory (Chemistry), DUST, INTERPLANETARY dust, ICE, ACTIVATION energy, COLLISION induced dissociation, METHANOL as fuel
Abstract

A consensus has progressively developed that the path towards complex organic molecules could be favoured by the icy mantles of interstellar dust particles. However, the question of whether activation energy is required to promote those reactions is open. This work deals with the simplest process thought to increase complexity i.e. successive additions of a single atom (H). Two situations can be considered, the direct additions of H in the gas phase and the atomic hydrogenation processes on water ice surfaces available in the interstellar medium (ISM). The synthesis of methanol, largely discussed in the literature is revisited as a case study. Computational investigations of the reactions leading from CO to CH3OH show that, with [H...(H2O)n] complexes as hydrogenation vectors, all steps of the process are barrier-less, contrary to the gas phase process and this, whatever the level of theory considered. The key parameter is the position of the CO + [H...(H2O)n] initial system on the global energy scale. At the present level of theory, when H is pre-adsorbed on the ice, the system happens to be high enough above the reaction path, namely, above any intermediates and possible transition states. This is true whatever the dimension of the ice support, even for the simplest model of one H2O molecule. Application of such a simplified synthetic approach, here validated for the synthesis of methanol, could be generalized, providing a simple way to get a fair insight into the important class of atomic hydrogenations on ices in the ISM. [ABSTRACT FROM AUTHOR]

Published
2023
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7. Protonated ions as systemic trapping agents for noble gases: From electronic structure to radiative association.

Author

Ozgurel, O., Pauzat, F., Pilmé, J., Ellinger, Y., Bacchus-Montabonel, M.-C., and Mousis, O.

Subjects
PROTONS, IONS, NOBLE gases, NONMETALS, ELECTRONIC structure, RADIATIVE flow
Abstract

The deficiencies of argon, krypton, and xenon observed in the atmosphere of Titan as well as anticipated in some comets might be related to a scenario of sequestration by H3+ in the gas phase at the early evolution of the solar nebula. The chemical process implied is a radiative association, evaluated as rather efficient in the case of H3+ , especially for krypton and xenon. This mechanism of chemical trapping might not be limited to H3+ only, considering that the protonated ions produced in the destruction of H3+ by its main competitors present in the primitive nebula, i.e., H2O, CO, and N2, might also give stable complexes with the noble gases. However the effective efficiency of such processes is still to be proven. Here, the reactivity of the noble gases Ar, Kr, and Xe, with all protonated ions issued from H2O, CO, and N2, expected to be present in the nebula with reasonably high abundances, has been studied with quantum simulation method dynamics included. All of them give stable complexes and the rate coefficients of their radiative associations range from 10-16 to 10-19 cm³ s-1, which is reasonable for such reactions and has to be compared to the rates of 10-16 to 10-18 cm³ s-1, obtained with H3+. We can consider this process as universal for all protonated ions which, if present in the primitive nebula as astrophysical models predict, should act as sequestration agents for all three noble gases with increasing efficiency from Ar to Xe. [ABSTRACT FROM AUTHOR]

Published
2017
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12. Communication: The formation of CHe2+ by radiative association.

Author

Zicler, E., Bacchus-Montabonel, M.-C., Pauzat, F., Chaquin, P., and Ellinger, Y.

Subjects
NOBLE gases, INTERSTELLAR medium, HELIUM, RADIATIVE flow, ACOUSTIC vibrations
Abstract

The detection of ArH+ has revived the interest in the search for noble gas containing species. Despite helium being the second most abundant element in the universe (He/H ~ 1/10), it has never been observed in any other form than that of a neutral/ionized atom in the interstellar medium. Because He is the "most noble" gas, its non-observation as part of neutral molecular systems is understandable. It is more surprising for charged species, especially HeH+ whose spectral signatures are well documented in the laboratory. The purpose of this work was to find a simple positive ion containing He, and likely to be observed as an alternative to undetected HeH+. Among the HeX2+ diatomics formed with first row atoms, we focused on X = C because of both its relative abundance and the magnitude of its ionization potentials with respect to He. The formation of CHe2+ by radiative association is the center of this study. The question was addressed by means of numerical simulations using high level ab initio calculations of the CHe2+ potential surface, followed by a quantum chemical determination of the rate coefficients for the corresponding radiative association in the range of 10 to 1000K. The radiative association path shows a potential well deep enough to accommodate 20 vibrational levels, and no barrier to oppose the reaction. The rate coefficient varies from ~ 4.5 × 10-20 cm3s-1 to ~ 2.5 × 10-22 cm3s-1 for the temperatures considered. The present study suggests that the existence of this species has to be searched for mainly in highly irradiated regions. [ABSTRACT FROM AUTHOR]

Published
2016
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15. Formation of amines: hydrogenation of nitrile and isonitrile as selective routes in the interstellar medium

Author

Nguyen, T, Fourre, I, Favre, C., Barois, C., Congiu, E., Baouche, S., Guillemin, J-C, Ellinger, Y., Dulieu, F., Nguyen, T, Fourre, I, Favre, C., Barois, C., Congiu, E., Baouche, S., Guillemin, J-C, Ellinger, Y., and Dulieu, F.

Abstract

Context. Beyond NH3, only one primary alkylamine, CH3NH2, has been identified in the interstellar medium and the reason why is still not understood: its formation could occur in the gas phase or in icy environments. Aims. To consider any possible difference between the formation of primary and secondary amines, we studied the hydrogenation processes of CH3CN and CH3NC, which would lead to the simple primary CH3CH2NH2 and secondary CH3NHCH3 amines, respectively. Methods. Experimentally, the hydrogenation of CH3CN and CH3NC was carried out under ultra-high vacuum, using two beamlines to inject the nitrile/isonitrile and H onto substrate surfaces of gold or water ice. The reactions were monitored using infrared spectroscopy and the products were followed by mass spectrometry. Theoretically, the energetics of the hydrogenation paths were determined using the M06-2X functional after benchmarking against post Hartree-Fock procedures. Meanwhile, a survey of the high-mass star forming region W51/e2 has been performed. Results. Following co-deposition of CH3CN and H, we show that these species do not react together between 10 and 60 K. For CH3NC we found that the hydrogenation process works all the way through the CH3NHCH3 end product; we also identified the CH3NCH2 intermediate together with side products, CH4 and HCN, showing that the isonitrile backbone is breaking. These results are consistent with the calculations of a high barrier on the first hydrogenation step for CH3CN and a lower barrier for CH3NC. Conclusions. The formation of CH3CH2NH2 by hydrogenation of CH3CN appears rather unlikely in both the gas phase and ice environment whereas that of CH3NHCH3 is a clear possibility. The limiting factor appears to be the efficiency of the tunneling effect through the first activation barrier on the reaction paths. More surveys are required for further insight into the search for amines.

Published
2019

16. Nitrile versus isonitrile adsorption at interstellar grain surfaces: II. Carbonaceous aromatic surfaces

Author

Bertin, M., Doronin, M., Michaut, X., Philippe, L., Markovits, A., Fillion, J.-H., Pauzat, F., Ellinger, Y., Guillemin, J.-C., Laboratoire d'Etude du Rayonnement et de la Matière en Astrophysique (LERMA), École normale supérieure - Paris (ENS Paris), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université de Cergy Pontoise (UCP), Université Paris-Seine-Université Paris-Seine-Centre National de la Recherche Scientifique (CNRS), Laboratoire de chimie théorique (LCT), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), Institut des Sciences Chimiques de Rennes (ISCR), Université de Rennes 1 (UR1), Université de Rennes (UNIV-RENNES)-Université de Rennes (UNIV-RENNES)-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)-Ecole Nationale Supérieure de Chimie de Rennes (ENSCR)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), PCMI, ANR-11-10EX-0004-02, Labex MiChem, École normale supérieure - Paris (ENS-PSL), Université de Rennes (UR)-Institut National des Sciences Appliquées - Rennes (INSA Rennes), and 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)

Subjects
astrochemistry, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], ISM: abundances, ISM: molecules
Abstract

International audience; Context. Almost 20% of the ~200 different species detected in the interstellar and circumstellar media present a carbon atom linked to nitrogen by a triple bond. Of these 37 molecules, 30 are nitrile R-CN compounds, the remaining 7 belonging to the isonitrile R-NC family. How these species behave in their interactions with the grain surfaces is still an open question. Aims. In a previous work, we have investigated whether the difference between nitrile and isonitrile functional groups may induce differences in the adsorption energies of the related isomers at the surfaces of interstellar grains of various nature and morphologies. This study is a follow up of this work, where we focus on the adsorption on carbonaceous aromatic surfaces. Methods. The question is addressed by means of a concerted experimental and theoretical approach of the adsorption energies of CH3CN and CH3NC on the surface of graphite (with and without surface defects). The experimental determination of the molecule and surface interaction energies is carried out using temperature-programmed desorption in an ultra-high vacuum between 70 and 160 K. Theoretically, the question is addressed using first-principle periodic density functional theory to represent the organised solid support.Results. The adsorption energy of each compound is found to be very sensitive to the structural defects of the aromatic carbonaceous surface: these defects, expected to be present in a large numbers and great diversity on a realistic surface, significantly increase the average adsorption energies to more than 50% as compared to adsorption on perfect graphene planes. The most stable isomer (CH3CN) interacts more efficiently with the carbonaceous solid support than the higher energy isomer (CH3NC), however.

Published
2017
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19. TRAPPING OF NOBLE GASES BY RADIATIVE ASSOCIATION WITH ${{\rm{H}}}_{3}^{+}$ IN THE PROTOSOLAR NEBULA

Author

Bacchus-Montabonel, Marie-Christine, Pauzat, F., Bacchus-Montabonel, M-C., Ellinger, Y., Mousis, O., Laboratoire de chimie théorique (LCT), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), Institut Lumière Matière [Villeurbanne] (ILM), Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Centre National de la Recherche Scientifique (CNRS), 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), 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 Pierre et Marie Curie - Paris 6 (UPMC)-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), and Université Bourgogne Franche-Comté [COMUE] (UBFC)-Université Bourgogne Franche-Comté [COMUE] (UBFC)

Subjects
Physics, Nebula, Astrochemistry, Comet, Noble gas, Astronomy and Astrophysics, Trapping, Astrophysics, 010402 general chemistry, 7. Clean energy, 01 natural sciences, 0104 chemical sciences, [CHIM.THEO]Chemical Sciences/Theoretical and/or physical chemistry, symbols.namesake, Chemical thermodynamics, 13. Climate action, Space and Planetary Science, 0103 physical sciences, symbols, Radiative transfer, Atomic physics, Titan (rocket family), [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], 010303 astronomy & astrophysics, ComputingMilieux_MISCELLANEOUS
Abstract

International audience; The heavy noble gas deficiencies observed in Titan's atmosphere and in comets have been proposed to be related to a sequestration process by H-3(+) in the gas phase at the early protosolar nebula. Chemical thermodynamics and astrophysics modeling are favorable to this hypothesis, as presented in preceding papers. However, there is a point still to be raised, i.e., that no dynamical study of the efficiency of the collisional processes had been performed so far. Here, we show that, apart from the expected exception of Ne, the rate constants obtained, i.e., 0.7 x 10(-18), 0.5 x 10(-16), and 10(-16) (cm(3) s(-1)) for Ar, Kr, and Xe, respectively, are reasonably high for such processes, particularly in the case of Kr and Xe. The temperature dependence is also considered, showing a similar behavior for all noble gases with a peak efficiency in the range 50-60 K. Globally, we can conclude that the scenario of sequestration by H-3(+) is definitively comforted by the results of our quantum dynamical treatment. This process may also be responsible of the Ar impoverishment just measured in comet 67P/Churyumov-Gerasimenko by the ROSINA mass spectrometer on board the Rosetta spacecraft.

Published
2016
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23. Neutral Na in comet tails: a chemical story

Author

Ellinger, Y., Pauzat, F., Mousis, O., Guilbert-Lepoutre, A., Leblanc, François, Ali-Dib, M., Doronin, M., Zicler, E., Doressoundiram, A., Laboratoire de chimie théorique (LCT), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), 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), Observatoire de Besançon, 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), Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université de Franche-Comté (UFC), HELIOS - LATMOS, Laboratoire Atmosphères, Milieux, Observations Spatiales (LATMOS), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-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 de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Laboratoire d'Etude du Rayonnement et de la Matière en Astrophysique (LERMA (UMR_8112)), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Cergy Pontoise (UCP), Université Paris-Seine-Université Paris-Seine-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Laboratoire d'études spatiales et d'instrumentation en astrophysique (LESIA), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS), 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 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), Sorbonne Université (SU)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université de Cergy Pontoise (UCP), Université Paris-Seine-Université Paris-Seine-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL), and Cardon, Catherine

Subjects
[SDU.ASTR.SR]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Solar and Stellar Astrophysics [astro-ph.SR], [SDU.ASTR.SR] Sciences of the Universe [physics]/Astrophysics [astro-ph]/Solar and Stellar Astrophysics [astro-ph.SR], [SDU.ASTR.EP]Sciences of the Universe [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], Astrophysics::Earth and Planetary Astrophysics
Abstract

International audience; The origin of the neutral sodium comet tail discovered in comet Hale-Bopp in 1997 is still a matter of discussion. Here we propose a scenario which is based on chemical grounds. The starting point is the chemical trapping of the Na+ ion in the refractory material during the condensation phase of the protosolar nebula, followed by its incorporation in the building blocks of the comets parent bodies. In the next step, the Na+ ions are washed out of the refractory material by the water formed by the melting of the ice due to the heat released in the radioactive decay of short period elements. When the water freezes again, the Na+ ion looses its positive charge to evolve progressively toward a neutral atom when approaching the surface of the ice. As shown by high-level numerical simulations based on first principle periodic density functional theory (DFT) to describe the solid structure of the ice, it is a neutral Na that is ejected with the sublimation of the ice top layer

Published
2015

25. ORIGIN OF MOLECULAR OXYGEN IN COMET 67P/CHURYUMOV–GERASIMENKO

Author

Mousis, O., primary, Ronnet, T., additional, Brugger, B., additional, Ozgurel, O., additional, Pauzat, F., additional, Ellinger, Y., additional, Maggiolo, R., additional, Wurz, P., additional, Vernazza, P., additional, Lunine, J. I., additional, Luspay-Kuti, A., additional, Mandt, K. E., additional, Altwegg, K., additional, Bieler, A., additional, Markovits, A., additional, and Rubin, M., additional

Published
2016
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29. The Composition of the Protosolar Disk and the Formation Conditions for Comets

Author

Willacy, K., primary, Alexander, C., additional, Ali-Dib, M., additional, Ceccarelli, C., additional, Charnley, S. B., additional, Doronin, M., additional, Ellinger, Y., additional, Gast, P., additional, Gibb, E., additional, Milam, S. N., additional, Mousis, O., additional, Pauzat, F., additional, Tornow, C., additional, Wirström, E. S., additional, and Zicler, E., additional

Published
2015
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32. Origin of Molecular Oxygen in Comets: Current Knowledge and Perspectives.

Author

Luspay-Kuti A, Mousis O, Lunine JI, Ellinger Y, Pauzat F, Raut U, Bouquet A, Mandt KE, Maggiolo R, Ronnet T, Brugger B, Ozgurel O, and Fuselier SA

Abstract

The Rosetta Orbiter Spectrometer for Ion and Neutral Analysis (ROSINA) instrument onboard the Rosetta spacecraft has measured molecular oxygen (O 2 ) in the coma of comet 67P/Churyumov-Gerasimenko (67P/C-G) in surprisingly high abundances. These measurements mark the first unequivocal detection of O 2 in a cometary environment. The large relative abundance of O 2 in 67P/C-G despite its high reactivity and low interstellar abundance poses a puzzle for its origin in comet 67P/C-G, and potentially other comets. Since its detection, there have been a number of hypotheses put forward to explain the production and origin of O 2 in the comet. These hypotheses cover a wide range of possibilities from various in situ production mechanisms to protosolar nebula and primordial origins. Here, we review the O 2 formation mechanisms from the literature, and provide a comprehensive summary of the current state of knowledge of the sources and origin of cometary O 2 .

Published
2018
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