Composition-dependent outgassing of comet 67P/Churyumov-Gerasimenko from ROSINA/DFMS. Implications for nucleus heterogeneity?
Wurz, P.; Altwegg, K.; Balsiger, H.; Berthelier, J. J.; Fuselier, S. A.; Fiethe, B.; Gasc, S.; Gombosi, T. I.; Le Roy, L.; Rubin, M.; Tzou, C. -Y.; Mall, U.; Mousis, O.; Hässig, M.; Jäckel, A.; Mandt, K. E.; Dhooghe, F.; Luspay-Kuti, A.
United States, Switzerland, France, Belgium, Germany
Abstract
Context. Early measurements of Rosetta's target comet, 67P/Churyumov-Gerasimenko (67P), showed a strongly heterogeneous coma in H2O, CO, and CO2.
Aims: The purpose of this work is to further investigate the coma heterogeneity of 67P, and to provide predictions for the near-perihelion outgassing profile based on the proposed explanations.
Methods: Measurements of various minor volatile species by ROSINA/DFMS on board Rosetta are examined. The analysis focuses on the currently poorly illuminated winter (southern) hemisphere of 67P.
Results: Coma heterogeneity is not limited to the major outgassing species. Minor species show better correlation with either H2O or CO2. The molecule CH4 shows a different diurnal pattern from all other analyzed species. Such features have implications for nucleus heterogeneity and thermal processing.
Conclusions: Future analysis of additional volatiles and modeling the heterogeneity are required to better understand the observed coma profile.