1
|
Combi M, Shou Y, Fougere N, Tenishev V, Altwegg K, Rubin M, Bockelée-Morvan D, Capaccioni F, Cheng YC, Fink U, Gombosi T, Hansen KC, Huang Z, Marshall D, Toth G. The Surface Distributions of the Production of the Major Volatile Species, H 2O, CO 2, CO and O 2, from the Nucleus of Comet 67P/Churyumov-Gerasimenko throughout the Rosetta Mission as Measured by the ROSINA Double Focusing Mass Spectrometer. Icarus 2020; 335:113421. [PMID: 31631900 PMCID: PMC6800715 DOI: 10.1016/j.icarus.2019.113421] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/15/2023]
Abstract
The Rosetta Orbiter Spectrometer for Ion and Neutral Analysis (ROSINA) suite of instruments operated throughout the over two years of the Rosetta mission operations in the vicinity of comet 67P/Churyumov-Gerasimenko. It measured gas densities and composition throughout the comet's atmosphere, or coma. Here we present two-years' worth of measurements of the relative densities of the four major volatile species in the coma of the comet, H2O, CO2, CO and O2, by one of the ROSINA sub-systems called the Double Focusing Mass Spectrometer (DFMS). The absolute total gas densities were provided by the Comet Pressure Sensor (COPS), another ROSINA sub-system. DFMS is a very high mass resolution and high sensitivity mass spectrometer able to resolve at a tiny fraction of an atomic mass unit. We have analyzed the combined DFMS and COPS measurements using an inversion scheme based on spherical harmonics that solves for the distribution of potential surface activity of each species as the comet rotates, changing solar illumination, over short time intervals and as the comet changes distance from the sun and orientation of its spin axis over long time intervals. We also use the surface boundary conditions derived from the inversion scheme to simulate the whole coma with our fully kinetic Direct Simulation Monte Carlo model and calculate the production rates of the four major species throughout the mission. We compare the derived production rates with revised remote sensing observations by the Visible and Infrared Thermal Imaging Spectrometer (VIRTIS) as well as with published observations from the Microwave Instrument for the Rosetta Orbiter (MIRO). Finally we use the variation of the surface production of the major species to calculate the total mass loss over the mission and, for different estimates of the dust/gas ratio, calculate the variation of surface loss all over the nucleus.
Collapse
Affiliation(s)
- Michael Combi
- Department of Climate and Space Sciences and Engineering, University of Michigan, Ann Arbor, Michigan, USA
| | - Yinsi Shou
- Department of Climate and Space Sciences and Engineering, University of Michigan, Ann Arbor, Michigan, USA
| | - Nicolas Fougere
- Department of Climate and Space Sciences and Engineering, University of Michigan, Ann Arbor, Michigan, USA
| | - Valeriy Tenishev
- Department of Climate and Space Sciences and Engineering, University of Michigan, Ann Arbor, Michigan, USA
| | - Kathrin Altwegg
- Physikalisches Institut, University of Bern, Bern, Switzerland
| | - Martin Rubin
- Physikalisches Institut, University of Bern, Bern, Switzerland
| | - Dominique Bockelée-Morvan
- LESIA, Observatoire de Paris, PSL Research University, CNRS, Sorbonne Universites, UPMC Univ. Paris 06, Univ. Paris-Diderot, Sorbonne Paris Cité, 5 place Jules Janssen, F-92195 Meudon, France
| | - Fabrizio Capaccioni
- 4INAF-IAPS, Istituto di Astrofisica e Planetologia Spaziali, via del fosso del Cavaliere 100, I-00133 Rome, Italy
| | - Yu-Chi Cheng
- LESIA, Observatoire de Paris, PSL Research University, CNRS, Sorbonne Universites, UPMC Univ. Paris 06, Univ. Paris-Diderot, Sorbonne Paris Cité, 5 place Jules Janssen, F-92195 Meudon, France
| | - Uwe Fink
- Lunar and Planetary Laboratory, University of Arizona, Tucson, Arizona, USA
| | - Tamas Gombosi
- Department of Climate and Space Sciences and Engineering, University of Michigan, Ann Arbor, Michigan, USA
| | - Kenneth C Hansen
- Department of Climate and Space Sciences and Engineering, University of Michigan, Ann Arbor, Michigan, USA
| | - Zhenguang Huang
- Department of Climate and Space Sciences and Engineering, University of Michigan, Ann Arbor, Michigan, USA
| | - David Marshall
- Max-Planck-Institut für Sonnensystemforschung, Justus-von-Liebig-Weg 3, 37077 Göttingen, Germany
| | - Gabor Toth
- Department of Climate and Space Sciences and Engineering, University of Michigan, Ann Arbor, Michigan, USA
| |
Collapse
|