Measurement of the Gas Environment of comet 67P/Churyumov-Gerasimenko with the Alice Far-ultraviolet Spectrograph on Rosetta

Wednesday, 17 December 2014: 2:10 PM
Paul D Feldman1, Michael F A'Hearn2, Jean-Loup Bertaux3, Lori M Feaga4, Joel Wm Parker5, Eric Schindhelm5, Andrew J Steffl6, S Alan Stern7 and Harold A Weaver Jr8, (1)Johns Hopkins University, Baltimore, MD, United States, (2)University of Maryland College Park, College Park, MD, United States, (3)University of Versailles Saint-Quentin en Yvelines, Versailles, France, (4)University of Maryland, College Park, MD, United States, (5)Southwest Research Institute Boulder, Boulder, CO, United States, (6)Southwest Research Institute, Boulder, CO, United States, (7)Southwest Research Institute Boulder, Dept Space Studies, Boulder, CO, United States, (8)The Johns Hopkins University, Laurel, MD, United States
Alice is a lightweight, low-power far-ultraviolet (750 – 2000 Å) spectrograph onboard Rosetta designed for in situ imaging spectroscopy of a cometary coma during the rendezvous with comet 67P/Churyumov-Gerasimenko. Among its primary objectives is the determination of the production rates and spatial distributions of the key parent species H2O, CO, and CO2, their atomic dissociation products, and their evolution as the comet approaches perihelion in August 2015. Following successful instrument re-commissioning in March 2014, Alice began to search for CO emission as Rosetta approached the comet during June and July 2014. Through this period only upper limits were obtained. Subsequent observations made during the pre-landing phases of the mission will also be presented and discussed in the context of contemporaneous in situ and other remote sensing measurements.