1. ROSINA/DFMS and IES observations of 67P: Ion-neutral chemistry in the coma of a weakly outgassing comet
- Author
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André Bieler, M. Rinaldi, Martin Rubin, Michael R. Combi, Thierry Sémon, Kathrin Altwegg, J. H. Waite, Hans Balsiger, Jean-Jacques Berthelier, Stephen A. Fuselier, J. De Keyser, Myrtha Hässig, Chia-Yu Tzou, C. Briois, Peter Wurz, Herbert Gunell, Henri Rème, Kirk C. Hansen, Susarla Raghuram, Ulrich Mall, Gaël Cessateur, M. Galand, S. M. Petrinec, Annette Jäckel, A. Korth, James L. Burch, K. J. Trattner, E. Vigren, B. Fiethe, Tamas I. Gombosi, Kathleen Mandt, Léna Le Roy, T. W. Broiles, Ursina Calmonte, Sébastien Gasc, Space Science Division [San Antonio], Southwest Research Institute [San Antonio] ( SwRI ), UTSA Department of Physics and Astronomy [San Antonio], The University of Texas at San Antonio ( UTSA ), Physikalisches Institut [Bern], Universität Bern [Bern], IMPEC - 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], Laboratoire de Physique et Chimie de l'Environnement et de l'Espace ( LPC2E ), Centre National de la Recherche Scientifique ( CNRS ) -Université d'Orléans ( UO ) -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 [Braunschweig], Imperial College London, Max Planck Institute for Solar System Research ( MPS ), Lockheed Martin Advanced Technology Center ( ATC ), Institut de recherche en astrophysique et planétologie ( IRAP ), Université Paul Sabatier - Toulouse 3 ( UPS ) -Observatoire Midi-Pyrénées ( OMP ) -Centre National de la Recherche Scientifique ( CNRS ), Laboratory for Atmospheric and Space Physics [Boulder] ( LASP ), University of Colorado Boulder [Boulder], Swedish Institute of Space Physics [Uppsala] ( IRF ), Southwest Research Institute [San Antonio] (SwRI), The University of Texas at San Antonio (UTSA), PLANETO - 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 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], Max Planck Institute for Solar System Research (MPS), Max-Planck-Gesellschaft, Lockheed Martin Advanced Technology Center (ATC), Institut de recherche en astrophysique et planétologie (IRAP), Institut national des sciences de l'Univers (INSU - CNRS)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Observatoire Midi-Pyrénées (OMP), Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Centre National de la Recherche Scientifique (CNRS), Laboratory for Atmospheric and Space Physics [Boulder] (LASP), University of Colorado [Boulder], Swedish Institute of Space Physics [Uppsala] (IRF), Universität Bern [Bern] (UNIBE), Max-Planck-Institut für Sonnensystemforschung = Max Planck Institute for Solar System Research (MPS), 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), and 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)
- Subjects
67P/Churyumov-Gerasimenko ,DYNAMICS ,Comet ,[SDU.ASTR.EP]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Earth and Planetary Astrophysics [astro-ph.EP] ,Data analysis ,Coma (optics) ,Astrophysics ,Astronomy & Astrophysics ,MASS ,Mass spectrometry ,Chemical reaction ,Ion ,METHANE ,Comet nucleus ,SPECTROMETER ,comets ,RATES ,HALLEY ,AMMONIA ,Science & Technology ,Chemistry ,comets: individual: 67P/Churyumov-Gerasimenko ,Astronomy and Astrophysics ,SENSOR ,plasmas ,[ SDU.ASTR.EP ] Sciences of the Universe [physics]/Astrophysics [astro-ph]/Earth and Planetary Astrophysics [astro-ph.EP] ,methods: data analysis ,Outgassing ,Solar wind ,molecular processes ,0201 Astronomical And Space Sciences ,solar wind ,INNER COMA ,13. Climate action ,Space and Planetary Science ,Physical Sciences ,P/HALLEY - Abstract
International audience; The Rosetta encounter with comet 67P/Churyumov-Gerasimenko provides a unique opportunity for an in situ, up-close investigation of ion-neutral chemistry in the coma of a weakly outgassing comet far from the Sun.Observations of primary and secondary ions and modeling are used to investigate the role of ion-neutral chemistry within the thin coma.Methods. Observations from late October through mid-December 2014 show the continuous presence of the solar wind 30 km from the comet nucleus. These and other observations indicate that there is no contact surface and the solar wind has direct access to the nucleus. On several occasions during this time period, the Rosetta/ROSINA/Double Focusing Mass Spectrometer measured the low-energy ion composition in the coma. Organic volatiles and water group ions and their breakup products (masses 14 through 19), CO2+ (masses 28 and 44) another mass peaks (at masses 26, 27 , and possibly 30) were observed. Secondary ions include H3O+ and HCO+ (masses 19 and 29). These secondary ions indicate ion-neutral chemistry in the thin coma of the comet. A relatively simple model is constructed to account for the low H3O+/H2O+ and HCO+/CO+ ratios observed in a water dominated coma. Results from this simple model are compared with results from models that include a more detailed chemical reaction network.At low outgassing rates, predictions from the simple model agree with observations and with results from more complex models that include much more chemistry. At higher outgassing rates, the ion-neutral chemistry is still limited and high HCO+/CO+ ratios are predicted and observed. However, at higher outgassing rates, the model predicts high H3O+/H2O+ ratios and the observed ratios are often low. These low ratios may be the result of the highly heterogeneous nature of the coma, where CO and CO2 number densities can exceed that of water.
- Published
- 2015
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