Rosetta/ROSINA observations of the volatiles in the coma of comet 67P/Churyumov-Gerasimenko during the nominal mission

Wednesday, 16 December 2015
Poster Hall (Moscone South)
Martin Rubin1, Kathrin Altwegg1, Hans R Balsiger1, Jean-Jacques Berthelier2, Ursina Calmonte1, Johan De Keyser3, Björn Fiethe4, Stephen A Fuselier5,6, Sébastien Gasc1, Tamas I Gombosi7, Myrtha Hässig8, Annette Jäckel1, Lena Le Roy9, Urs A. Mall10, Henri Rème11, Thierry Sémon1, Chia-yu Tzou1 and Peter Wurz1, (1)University of Bern, Bern, Switzerland, (2)CNRS, Paris Cedex 16, France, (3)Belgisch Instituut voor Ruimte-Aeronomie, Brussel, Belgium, (4)Technical University of Braunschweig, Braunschweig, Germany, (5)Southwest Research Institute, San Antonio, TX, United States, (6)University of Texas at San Antonio, Department of Physics & Astronomy, San Antonio, TX, United States, (7)Univ of Michigan, Ann Arbor, MI, United States, (8)Southwest Research Institute San Antonio, San Antonio, TX, United States, (9)University of Bern, Center for Space and Habitability, Bern, Switzerland, (10)Max Planck Institute for Solar System Research, Katlenburg-Lindau, Germany, (11)IRAP, Institut de Recherche en Astrophysique et Planétologie, Toulouse, France
The European Space Agency’s Rosetta spacecraft is in close proximity of comet 67P/Churyumov-Gerasimenko for well over a year now. During this time Rosetta followed the comet from almost 3.5 AU through perihelion at 1.25 AU and away from the Sun again. Part of the scientific payload scrutinizing the comet is the ROSINA experiment, the Rosetta Orbiter Spectrometer for Ion and Neutral Analysis. The suite of instruments consists of the Double Focusing Mass Spectrometer DFMS, the Reflectron Time-Of-Flight mass spectrometer RTOF, and the COmet Pressure Sensor COPS. From the combined measurements by ROSINA, the composition and dynamics of the volatiles in the coma of the comet are derived.

On 13 August 2015, comet 67P/Churyumov-Gerasimenko reached perihelion, the point along its orbits that is closest to the Sun. Furthermore equinox occurred in May 2015 leading to a change in season – the previous summer hemisphere is now in winter and vice versa.

One of the goals of ROSINA is to track the activity of the comet during its apparition and to investigate potential changes in the chemical composition as the spacecraft orbits around the nucleus. In this presentation we will summarize some key findings obtained during the first year and a half of the nominal mission and present first results comparing the pre- and post perihelion neutral gas coma. The goal of these observations is to gather information about the formation and the composition of the comet and ultimately our early Solar System.