Surface localization of gas sources on comet 67P/Churyumov-Gerasimenko based on DFMS/COPS data

Abstract

We reconstruct the temporal evolution of the source distribution for the four major gas species H2O, CO2, CO, and O2 on the surface of comet 67P/Churyumov-Gerasimenko during its 2015 apparition. The analysis applies an inverse coma model and fits to data between 2014 August 6 and 2016 September 5 measured with the Double FocusingMass Spectrometer (DFMS) of the Rosetta Orbiter Spectrometer for Ion and Neutral Analysis (ROSINA) and the COmet Pressure Sensor (COPS). The spatial distribution of gas sources with their temporal variation allows one to construct surface maps for gas emissions and to evaluate integrated production rates. For all species peak production rates and integrated production rates per orbit are evaluated separately for the Northern and Southern hemisphere. The nine most active emitting areas on the comet's surface are defined and their correlation to emissions for each of the species is discussed.