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13 results on '"Gasc S."'

1. ALMA and ROSINA detections of phosphorus-bearing molecules: the interstellar thread between star-forming regions and comets

Author

Rivilla, V. M., Drozdovskaya, M. N., Altwegg, K., Caselli, P., BELTRAN SOROLLA, MARIA TERESA, FONTANI, FRANCESCO, van der Tak, F. F. S., CESARONI, Riccardo, Vasyunin, A., Rubin, M., Lique, F., Marinakis, S., TESTI, Leonardo, Rosina Team, Balsiger, H., Berthelier, J. J., de Keyser, J., Fiethe, B., Fuselier, S. A., Gasc, S., Gombosi, T. I., Sémon, T., Tzou, C. -Y., INAF - Osservatorio Astrofisico di Arcetri (OAA), Istituto Nazionale di Astrofisica (INAF), Center for Space and Habitability (CSH), University of Bern, Physikalisches Institut [Bern], Universität Bern [Bern], Max-Planck-Institut für Extraterrestrische Physik (MPE), SRON Netherlands Institute for Space Research (SRON), Kapteyn Astronomical Institute [Groningen], University of Groningen [Groningen], Ural Federal University [Ekaterinburg] (UrFU), Laboratoire Ondes et Milieux Complexes (LOMC), Centre National de la Recherche Scientifique (CNRS)-Université Le Havre Normandie (ULH), Normandie Université (NU)-Normandie Université (NU), School of Health, Sport and Bioscience (HSB), University of East London (UEL), School of Biological and Chemical Sciences, Queen Mary University of London (QMUL), European Southern Observatory (ESO), PLANETO - LATMOS, Laboratoire Atmosphères, Milieux, Observations Spatiales (LATMOS), Sorbonne Université (SU)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS), Belgian Institute for Space Aeronomy / Institut d'Aéronomie Spatiale de Belgique (BIRA-IASB), Institute of Computer and Network Engineering [Braunschweig] (IDA), Technische Universität Braunschweig = Technical University of Braunschweig [Braunschweig], Southwest Research Institute [San Antonio] (SwRI), Department of Atmospheric, Oceanic, and Space Sciences [Ann Arbor] (AOSS), University of Michigan [Ann Arbor], University of Michigan System-University of Michigan System, and Astronomy

Subjects
Solar System, PN, Astrochemistry, molecular data, 530 Physics, Comet, SULFUR, FOS: Physical sciences, Astrophysics, 01 natural sciences, Submillimeter Array, ABUNDANCES, CHEMISTRY, Planet, FORMATION [STARS], Bipolar outflow, EXCITATION, 0103 physical sciences, Protostar, POTENTIAL-ENERGY SURFACES, 010306 general physics, 010303 astronomy & astrophysics, Solar and Stellar Astrophysics (astro-ph.SR), Physics, ASTROCHEMISTRY, PHOSPHINE, stars: formation, [SDU.ASTR]Sciences of the Universe [physics]/Astrophysics [astro-ph], astrochemistry, 520 Astronomy, comets: general, 67P/CHURYUMOV-GERASIMENKO, PROTOSTELLAR, Astronomy and Astrophysics, MOLECULAR DATA, 620 Engineering, Astrophysics - Astrophysics of Galaxies, ISM: molecules, Stars, Astrophysics - Solar and Stellar Astrophysics, 13. Climate action, Space and Planetary Science, MOLECULES [ISM], Astrophysics of Galaxies (astro-ph.GA), EMISSION, GENERAL [COMETS]
Abstract

To understand how Phosphorus-bearing molecules are formed in star-forming regions, we have analysed ALMA observations of PN and PO towards the massive star-forming region AFGL 5142, combined with a new analysis of the data of the comet 67P/Churyumov-Gerasimenko taken with the ROSINA instrument onboard Rosetta. The ALMA maps show that the emission of PN and PO arises from several spots associated with low-velocity gas with narrow linewidths in the cavity walls of a bipolar outflow. PO is more abundant than PN in most of the spots, with the PO/PN ratio increasing as a function of the distance to the protostar. Our data favor a formation scenario in which shocks sputter phosphorus from the surface of dust grains, and gas-phase photochemistry induced by UV photons from the protostar allows efficient formation of the two species in the cavity walls. Our analysis of the ROSINA data has revealed that PO is the main carrier of P in the comet, with PO/PN>10. Since comets may have delivered a significant amount of prebiotic material to the early Earth, this finding suggests that PO could contribute significantly to the phosphorus reservoir during the dawn of our planet. There is evidence that PO was already in the cometary ices prior to the birth of the Sun, so the chemical budget of the comet might be inherited from the natal environment of the Solar System, which is thought to be a stellar cluster including also massive stars., Accepted in MNRAS (20 pages, 12 figures)

Published
2019
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2. CLUPI, a high-performance Imaging System on the rover of theExoMars Mission 2020 to doscover biofabrics on MARS. Science objectives and development status

Author

Josset, J.-L., Westall, F., Hofmann, B. A., Spray, J., Cockell, C., Kempe, S., Griffiths, A. D., De Sanctis, Maria Cristina, Colangeli, Luigi, Koschny, D., Föllmi, Karl, Verrecchia, Eric, Diamond, Larryn, Josset, Marie, Javaux, Emmanuelle J., Esposito, F., Gunn, M., Gasc, S., Bontognali, Tomaso R. R., Korablev, Oleg, Erkman, Suren, Paar, G., Ulamec, Stephan, Foucher, F., Kuhn, N., Tanevski, M., Martin, P., and Yago, J.

Subjects
ExoMars, CLUPI
Published
2018

3. 2 years with comet 67P/Churyumov-Gerasimenko: H2O, CO2, CO as seen by ROSINA RTOF

Author

Hoang, M., Garnier, P., Lasue, J., Reme, H., Altwegg, K., Balsiger, H. R., Bieler, A. M., Calmonte, U., CAPRIA, MARIA TERESA, Combi, M. R., De Keyser, J. M., Fiethe, B., Fougere, N., Fuselier, S. A., Galli, A., Gasc, S., Gombosi, T. I., Hansen, K. C., Jäckel, A., Korth, A., Mall, U., MIGLIORINI, Alessandra, Rubin, M., Sémon, T., Tzou, C. Y., Waite, J. H., Jr., Wurz, P., ITA, USA, FRA, DEU, BEL, and CHE

Abstract

The Rosetta space mission investigated comet 67P/Churyumov-Gerasimenko (67P) over two years from August 2014 to September 2016. Onboard the spacecraft, the ROSINA experiment included two mass spectrometers to derive the composition of neutrals and ions, and a COmet Pressure Sensor (COPS) to monitor the density and velocity of the neutrals in the coma. We will here analyse and discuss data from the Reflectron-type Time-Of-Flight instrument during the comet escort phase. The RTOF mass spectrometer possessed a wide mass range and a high temporal resolution (Balsiger et al., 2007). The analysis of 67P/C-G's coma major molecules over the mission showed strong variability of the comet coma's main volatiles concentrations (H2O, CO2, CO) and their relative abundances. The 2 years long Rosetta mission allowed us to observe the seasonal evolution in the atmosphere of 67P, in particular the change occurring during the equinoxes and at perihelion. In this work, we analyze the asymmetry in the outgassing rate before and after the perihelion (13/08/2015), the evolution of abundance ratios through the whole mission, and in particular the behavior of the very volatile CO molecules. Density maps projected on the surface of 67P demonstrate the evolution of the three main coma species after the outbound equinox. We will present first results of our comet nucleus thermal modelling used to simulate the internal structure and temperature evolution of 67P at characteristic surface areas. These results will be compared with the coma composition measurements obtained by ROSINA....

Published
2017

4. Noble gases Ar, Kr and Xe measured in the coma of Comet 67P/Churyumov-Gerasimenko: implications to early solar system formation

Author

Balsiger, H. R., Altwegg, K., Bar-Nun, A., Berthelier, Jean-Jacques, Bieler, A. M., Bochsler, P., Briois, C., Calmonte, U., Combi, M. R., de Keyser, J., Fiethe, B., Fuselier, S. A., Gasc, S., Gombosi, T. I., Hansen, K. C., Hässig, M., Kopp, E., Korth, A., Le Roy, L., Mall, U., Marty, B., Mousis, O., Owen, T. C., Reme, H., Rubin, M., Semon, T., Tzou, C. Y., Waite, J. H., Wurz, P., Physikalisches Institut [Bern], Universität Bern [Bern] (UNIBE), Center for Space and Habitability (CSH), University of Bern, Tel Aviv University (TAU), PLANETO - LATMOS, Laboratoire Atmosphères, Milieux, Observations Spatiales (LATMOS), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), University of Michigan [Ann Arbor], University of Michigan System, Laboratoire de Physique et Chimie de l'Environnement et de l'Espace (LPC2E), Observatoire des Sciences de l'Univers en région Centre (OSUC), 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 d'Orléans (UO)-Centre National de la Recherche Scientifique (CNRS)-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 d'Orléans (UO)-Centre National de la Recherche Scientifique (CNRS)-Centre National d’Études Spatiales [Paris] (CNES), Belgian Institute for Space Aeronomy / Institut d'Aéronomie Spatiale de Belgique (BIRA-IASB), Technische Universität Braunschweig = Technical University of Braunschweig [Braunschweig], Southwest Research Institute [San Antonio] (SwRI), Max-Planck-Institut für Sonnensystemforschung = Max Planck Institute for Solar System Research (MPS), Max-Planck-Gesellschaft, Centre de Recherches Pétrographiques et Géochimiques (CRPG), Institut national des sciences de l'Univers (INSU - CNRS)-Université de Lorraine (UL)-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), University of Hawai‘i [Mānoa] (UHM), Institut de recherche en astrophysique et planétologie (IRAP), Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP), Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Centre National de la Recherche Scientifique (CNRS), and POTHIER, Nathalie

Subjects
[SDU] Sciences of the Universe [physics], Surfaces, Plasma, [SDU]Sciences of the Universe [physics], Ices, Physics::Space Physics, Comets, Astrophysics::Solar and Stellar Astrophysics, Dust, Astrophysics::Earth and Planetary Astrophysics, MHD instabilities, Small Bodies
Abstract

International audience; The role of comets in the formation of solar system planets, in particular their contribution to the volatiles of the terrestrial planets has been the subject of numerous models and speculations. Having kept at least partially the volatile constituents of the solar nebula, comets are among the most primitive objects in the solar system. Noble gases in the cometary coma are key tracers for assessing origin and processing of planetary atmospheres. We report the detection of Ar, Kr and Xe in the coma of Comet 67P during the same period (May 2016) by the Double Focusing Mass Spectrometer (DFMS) of the ROSINA experiment on ESA's Rosetta spacecraft, their relative abundance and isotopic composition. First implications for the volatile inventory of terrestrial planets and for solar system formation scenarios are discussed.

Published
2016

5. Evolution of water production of 67P/Churyumov-Gerasimenko

Author

Hansen, Kenneth C., Altwegg, K., Berthelier, J. -J., Bieler, A., Biver, N., Bockelee-Morvan, D., Calmonte, U., Capaccioni, F., Combi, M. R., De Keyser, J., Fiethe, B., Fougere, N., Fuselier, S. A., Gasc, S., Gombosi, T. I., Huang, Z., Le Roy, L., Lee, S., Nilsson, H., Rubin, Martin, Shou, Y., Snodgrass, C., Tenishev, V., Tzou, C.-Y., Wedlund, C. Simon, Toth, Gabor, ROSINA Team, University of Michigan, Ann Arbor, University of Bern, Observatoire de Paris, Istituto Nazionale Astrofisica - Italy, Royal Belgian Institute for Space Aeronomy, TU Braunschweig, University of Texas at San Antonio, Jet Propulsion Laboratory, Swedish Institute of Space Physics, Open University, Department of Radio Science and Engineering, Aalto-yliopisto, and Aalto University

Subjects
individual: 67P/CG [comets], SIMULATION, DUST, CO2, PREPERIHELION, ROSINA, PERIHELION, miscellaneous [methods], ATMOSPHERE, ROSETTA ORBITER, TARGET COMET 67P/CHURYUMOV-GERASIMENKO, general [comets], HALE-BOPP
Abstract

We examine the evolution of the water production of comet 67P/Churyumov-Gerasimenko during the Rosetta mission (2014 June-2016 May) based on in situ and remote sensing measurements made by Rosetta instruments, Earth-based telescopes and through the development of an empirical coma model. The derivation of the empirical model is described and the model is then applied to detrend spacecraft position effects from the Rosetta Orbiter Spectrometer for Ion and Neutral Analysis (ROSINA) data. The inter-comparison of the instrument data sets shows a high level of consistency and provides insights into the water and dust production. We examine different phases of the orbit, including the early mission (beyond 3.5 au) where the ROSINA water production does not show the expected increase with decreasing heliocentric distance. A second important phase is the period around the inbound equinox, where the peak water production makes a dramatic transition from northern to southern latitudes. During this transition, the waterdistribution is complex, but is driven by rotation and active areas in the north and south. Finally, we consider the perihelion period, where there may be evidence of time dependence in the water production rate. The peak water production, as measured by ROSINA, occurs 18-22 d after perihelion at 3.5 +/- 0.5 x 10(28) water molecules s(-1). We show that the water production is highly correlated with ground-based dust measurements, possibly indicating that several dust parameters are constant during the observed period. Using estimates of the dust/gas ratio, we use our measured water production rate to calculate a uniform surface loss of 2-4 m during the current perihelion passage.

Published
2016

6. The volatile inventory of comet 67P/Churyumov-Gerasimenko from Rosetta/ROSINA at 3 AU

Author

Le Roy, L., Altwegg, K., Berthelier, Jean-Jacques, Bieler, A., Briois, C., Calmonte, U., Combi, M. R., de Keyser, J., Dhooghe, F., Fiethe, B., Fuselier, S. A., Gasc, S., Gombosi, T. I., Hässig, M., Jäckel, A., Rubin, M., Tzou, C. -Y., Center for Space and Habitability (CSH), University of Bern, Space Research and Planetary Sciences [Bern) (WP), Physikalisches Institut [Bern], Universität Bern [Bern] (UNIBE)-Universität Bern [Bern] (UNIBE), 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), Department of Atmospheric, Oceanic, and Space Sciences [Ann Arbor] (AOSS), University of Michigan [Ann Arbor], University of Michigan System-University of Michigan System, Laboratoire de Physique et Chimie de l'Environnement et de l'Espace (LPC2E), Observatoire des Sciences de l'Univers en région Centre (OSUC), 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 d'Orléans (UO)-Centre National de la Recherche Scientifique (CNRS)-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 d'Orléans (UO)-Centre National de la Recherche Scientifique (CNRS)-Centre National d’Études Spatiales [Paris] (CNES), Belgian Institute for Space Aeronomy / Institut d'Aéronomie Spatiale de Belgique (BIRA-IASB), Institute of Computer and Network Engineering [Braunschweig] (IDA), Technische Universität Braunschweig = Technical University of Braunschweig [Braunschweig], and Southwest Research Institute [San Antonio] (SwRI)

Subjects
[SDU]Sciences of the Universe [physics]
Abstract

International audience; Comets are believed to be the most pristine bodies in the solar system. The study of their composition can therefore give us important clues about the processes that occurred during the solar system formation. We will report abundances of the major observed species with focus on the hydrocarbons detected by ROSINA/DFMS in the coma of 67P/Churyumov-Gerasimenko in October 2014 at 3 AU.

Published
2015

8. Physical Characterization of Asteroids Candidates of Marco Polo Mission

Author

Birlan, Mirel, Binzel, Richard P., Nedelcu, Dan Alin, Vernazza, Pierre, Barucci, Maria Antonella, Gasc, S., Fulchignoni, Marcello, Dotto, Elisabetta, Institut de Mécanique Céleste et de Calcul des Ephémérides (IMCCE), 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 de Lille-Centre National de la Recherche Scientifique (CNRS), Department of Earth Atmospheric and Planetary Sciences, MIT, AIRA, Romania, ESTEC / ESA, Netherlands, Laboratoire d'études spatiales et d'instrumentation en astrophysique (LESIA), 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), Pôle Planétologie du LESIA, Laboratoire d'études spatiales et d'instrumentation en astrophysique = Laboratory of Space Studies and Instrumentation in Astrophysics (LESIA), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Cité (UPCité)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Cité (UPCité), Université Paris Cité (UPCité), and INAF/OAR, Italy

Subjects
[PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph]
Abstract

International audience; The principal scientific objective of the Marco Polo mission is to return unaltered NEO materials. Marco Polo will allow us to analyze the samples in terrestrial laboratories, thereby obtaining measurements that cannot yet beperformed from a robotic spacecraft. The selection of the target asteroids for the mission has important consequences in terms of mission design, constraints, and operational requirements. A list of asteroids as possible targets for the Marco Polo mission has been drawn, taken into account both dynamical and physical constraints. The key parameters of this list were the accessibility of the object (the delta-V amount for the encounter with the target) and the desirable, primitive composition requirements of the target deduced from the groundbased data (mainly from colors and spectroscopy).

Published
2009

9. Les changements institutionnels dans la prise en charge des enfants handicapés en milieu ordinaire : les applications des lois de la réforme de la protection de l’enfance du 5 mars 2007 et du 11 février 2005 pour l’égalité des droits et des chances, la participation et la citoyenneté des personnes handicapées

Author

Atticot, Maurice, Bertrand, M., Besson, M., Blaison, M., Egly, C., Gasc, S., Heitz, JS., Levesque, E., MAURY, N., Milachon, N., Savoure, C., Bréhaux, Karine, brehaux, karine, Centre de recherches politiques de Sciences Po (Sciences Po, CNRS) (CEVIPOF), Sciences Po (Sciences Po)-Centre National de la Recherche Scientifique (CNRS), EHESP, and Centre de recherches politiques de Sciences Po (CEVIPOF)

Subjects
[SHS] Humanities and Social Sciences, [SHS]Humanities and Social Sciences
Published
2008

10. Prebiotic chemicals--amino acid and phosphorus--in the coma of comet 67P/Churyumov-Gerasimenko

Author

Altwegg K., Balsiger H., Bar-Nun A., Berthelier J.-J., Bieler A., Bochsler P., Briois C., Calmonte U., Combi M. R., Cottin H., De Keyser J., Dhooghe F., Fiethe B., Fuselier S. A., Gasc S., Gombosi T. I., Hansen K. C., Haessig M., Ja ckel A., Kopp E., Korth A., Le Roy L., Mall U., and Marty B.

Abstract

The importance of comets for the origin of life on Earth has been advocated for many decades. Amino acids are key ingredients in chemistry leading to life as we know it. Many primitive meteorites contain amino acids and it is generally believed that these are formed by aqueous alterations. In the collector aerogel and foil samples of the Stardust mission after the flyby at comet Wild 2 the simplest form of amino acids glycine has been found together with precursor molecules methylamine and ethylamine. Because of contamination issues of the samples a cometary origin was deduced from the C 13 isotopic signature. We report the presence of volatile glycine accompanied by methylamine and ethylamine in the coma of 67P/Churyumov Gerasimenko measured by the ROSINA (Rosetta Orbiter Spectrometer for Ion and Neutral Analysis) mass spectrometer confirming the Stardust results. Together with the detection of phosphorus and a multitude of organic molecules this result demonstrates that comets could have played a crucial role in the emergence of life on Earth.

Published
2016
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11. Cometary science. Time variability and heterogeneity in the coma of 67P/Churyumov-Gerasimenko

Author

Hässig M, Altwegg K, Balsiger H, Bar-Nun A, Berthelier J J, Bieler A, Bochsler P, Briois C, Calmonte U, Combi M, De Keyser J, Eberhardt P, Fiethe B, Fuselier S A, Galand M, Gasc S, Gombosi T I, Hansen K C, Jäckel A, Keller H U, Kopp E, Korth A, Kührt E, Le Roy L, and Mall U

Subjects
food and beverages, sense organs
Abstract

Comets contain the best preserved material from the beginning of our planetary system. Their nuclei and comae composition reveal clues about physical and chemical conditions during the early solar system when comets formed. ROSINA (Rosetta Orbiter Spectrometer for Ion and Neutral Analysis) onboard the Rosetta spacecraft has measured the coma composition of comet 67P/Churyumov Gerasimenko with well sampled time resolution per rotation. Measurements were made over many comet rotation periods and a wide range of latitudes. These measurements show large fluctuations in composition in a heterogeneous coma that has diurnal and possibly seasonal variations in the major outgassing species: water carbon monoxide and carbon dioxide. These results indicate a complex coma nucleus relationship where seasonal variations may be driven by temperature differences just below the comet surface.

Published
2015
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12. Protostellar and cometary detections of organohalogens

Author

Fayolle, E.C., Öberg, K.I., Jørgensen, J.K., Altwegg, K., Calcutt, H., Müller, H.S.P., Rubin, M., Wiel, M.H.D. van der, Bjerkeli, P., Bourke, T.L., Coutens, A., Dishoeck, E.F. van, Drozdovskaya, M.N., Garrod, R.T., Ligterink, N.F.W., Persson, M.V., Wampfler, S.F., Balsiger, H., Berthelier, J.J., De Keyser, J., Fiethe, B., Fuselier, S.A., Gasc, S., Gombosi, T.I., Semon, T., and Tzou, C.-Y.

Subjects
Physics, 010504 meteorology & atmospheric sciences, Comet, Astronomy, Astronomy and Astrophysics, 01 natural sciences, 7. Clean energy, Submillimeter Array, Exoplanet, Astrobiology, law.invention, Orbiter, 13. Climate action, law, Planet, 0103 physical sciences, Terrestrial planet, Protostar, Isotopologue, 010303 astronomy & astrophysics, 0105 earth and related environmental sciences
Abstract

Organohalogens, a class of molecules that contain at least one halogen atom bonded to carbon, are abundant on the Earth where they are mainly produced through industrial and biological processes1. Consequently, they have been proposed as biomarkers in the search for life on exoplanets2. Simple halogen hydrides have been detected in interstellar sources and in comets, but the presence and possible incorporation of more complex halogen-containing molecules such as organohalogens into planet-forming regions is uncertain3,4. Here we report the interstellar detection of two isotopologues of the organohalogen CH3Cl and put some constraints on CH3F in the gas surrounding the low-mass protostar IRAS 16293–2422, using the Atacama Large Millimeter/submillimeter Array (ALMA). We also find CH3Cl in the coma of comet 67P/Churyumov–Gerasimenko (67P/C-G) by using the Rosetta Orbiter Spectrometer for Ion and Neutral Analysis (ROSINA) instrument. The detections reveal an efficient pre-planetary formation pathway of organohalogens. Cometary impacts may deliver these species to young planets and should thus be included as a potential abiotical production source when interpreting future organohalogen detections in atmospheres of rocky planets.

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13. Impact of Radiogenic Heating on the Formation Conditions of Comet 67P/Churyumov–Gerasimenko

Author

Monnereau, M., Waite, J. H., Rème, H., Cessateur, G., De Keyser, J., Gasc, S., Korth, A., Berthelier, J.-J., Le Deun, T., Fuselier, S. A., Balsiger, H., Vernazza, P., Mall, U., Tzou, Chia-Yu, Maggiolo, R., Rubin, Martin, Lunine, J. I., Altwegg, Kathrin, Wurz, Peter, Drouard, A., Mousis, O., and Marty, B.

Subjects
13. Climate action, 530 Physics
Abstract

Because of the high fraction of refractory material present in comets, the heat produced by the radiogenic decay of elements such as aluminum and iron can be high enough to induce the loss of ultravolatile species such as nitrogen, argon, or carbon monoxide during their accretion phase in the protosolar nebula (PSN). Here, we investigate how heat generated by the radioactive decay of ²⁶Al and ⁶⁰Fe influences the formation of comet 7P/Churyumov–Gerasimenko, as a function of its accretion time and the size of its parent body. We use an existing thermal evolution model that includes various phase transitions, heat transfer in the ice-dust matrix, and gas diffusion throughout the porous material, based on thermodynamic parameters derived from Rosetta observations. Two possibilities are considered: either, to account for its bilobate shape, 67P/Churyumov–Gerasimenko was assembled from two primordial ~2 km sized planetesimals, or it resulted from the disruption of a larger parent body with a size corresponding to that of comet Hale–Bopp (∼70 km). To fully preserve its volatile content, we find that either 67P/Churyumov–Gerasimenko’s formation was delayed between ~2.2 and 7.7 Myr after that of Ca–Al-rich Inclusions in the PSN or the comet’s accretion phase took place over the entire time interval, depending on the primordial size of its parent body and the composition of the icy material considered. Our calculations suggest that the formation of 67P/Churyumov–Gerasimenko is consistent with both its accretion from primordial building blocks formed in the nebula or from debris issued from the disruption of a Hale–Bopp-like body.

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