The gas production of 14 species from comet 67P/Churyumov-Gerasimenko based on DFMS/COPS data from 2014-2016

TL;DR

This study analyzes in-situ measurements from Rosetta to quantify the production rates of 14 gas species from comet 67P/Churyumov-Gerasimenko over two years, revealing spatial and seasonal variations.

Contribution

It introduces a comprehensive inverse coma model to derive surface emission rates for 14 gases, including error bounds and temporal evolution, based on Rosetta data.

Findings

Quantified production rates of 14 gas species over 2 years.

Identified spatial differences between the comet's lobes and hemispheres.

Compared gas production with seasonal illumination patterns.

Abstract

The coma of comet 67P/Churyumov-Gerasimenko has been probed by the Rosetta spacecraft and shows a variety of different molecules. The ROSINA COmet Pressure Sensor and the Double Focusing Mass Spectrometer provide in-situ densities for many volatile compounds including the 14 gas species H2O, CO2, CO, H2S, O2, C2H6, CH3OH, H2CO, CH4, NH3, HCN, C2H5OH, OCS, and CS2. We fit the observed densities during the entire comet mission between August 2014 and September 2016 to an inverse coma model. We retrieve surface emissions on a cometary shape with 3996 triangular elements for 50 separated time intervals. For each gas we derive systematic error bounds and report the temporal evolution of the production, peak production, and the time-integrated total production. We discuss the production for the two lobes of the nucleus and for the northern and southern hemispheres. Moreover we provide a comparison of the gas production with the seasonal illumination.