A 3D Description of the Coma of Comet 67P/Churyumov-Gerasimenko Constrained by Rosetta Observations

International audience; For the first time, the Rosetta spacecraft stays with a comet over an extended period of time during its journey in the inner the solar system. The data provided by the suite of instruments on board the Rosetta spacecraft, notably the ROSINA mass spectrometers and the pressure sensor, provides critical information concerning comet 67P/Churyumov-Gerasimenko (CG) and its environment. These measurements reinforce our knowledge of comet CG and enable us to describe the nucleus and the sources with more details. The observations allow us to better constrain and accordingly develop much more realistic models of the comet’s coma.We show a 3D simulation of the gas and dust coma of comet CG using a Direct Simulation Monte-Carlo model performed with the Adaptive Mesh Particle Simulator (Tenishev et al. 2008, 2011). The coma model presented includes a realistic nucleus shape, with a gas flux distribution and a surface temperature that takes into account irregularities and concavities of the nucleus. Along with the gas drag, the gravity field drives the dust dynamics and is therefore accurately computed around the irregular nucleus shape. This constitutes the state-of-the-art of cometary coma models, which are crucial to interpret instrument data and for further mission planning.Acknowledgement:This work was supported by contracts JPL#1266313 and JPL#1266314 from the US Rosetta Project and NASA grant NNX09AB59G from the Planetary Atmospheres Program.References:Tenishev et al. 2008 ApJ 685:659, and 2011 ApJ 732:104