Composition-dependent outgassing of comet 67P/Churyumov-Gerasimenko from ROSINA/DFMS. Implications for nucleus heterogeneity?

A. Luspay-Kuti (1) , M. Hässig (1) , S. A. Fuselier (1) , K. E. Mandt (1) , Kathrin Altwegg (2, 3) , Hans Balsiger (3) , S. Gasc (3) , A. Jäckel (3) , Léna Le Roy (2) , M. Rubin (3) , C.-Y. Tzou (3) , P. Wurz (2, 3) , O. Mousis (4) , F. Dhooghe (5, 6) , Jean-Jacques Berthelier (7) , Björn Fiethe (8) , Tamas I. Gombosi (9) , U. Mall (10)

1 Space Science Division [San Antonio]
2 CSH - Center for Space and Habitability
3 Physikalisches Institut [Bern]
4 LAM - Laboratoire d'Astrophysique de Marseille
5 CmPA - Centre for Mathematical Plasma-Astrophysics [Leuven]
6 BIRA-IASB - Belgian Institute for Space Aeronomy / Institut d'Aéronomie Spatiale de Belgique
7 PLANETO - LATMOS
8 IDA - Institute of Computer and Network Engineering [Braunschweig]
9 AOSS - Department of Atmospheric, Oceanic, and Space Sciences [Ann Arbor]
10 MPS - Max Planck Institute for Solar System Research

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.

Keywords: comets; Data analysis; Observational method; 67P/Churyumov-Gerasimenko

Domains: Earth and Planetary Astrophysics [astro-ph.EP]

A. Luspay-Kuti, M. Hässig, S. A. Fuselier, K. E. Mandt, Kathrin Altwegg, et al.. Composition-dependent outgassing of comet 67P/Churyumov-Gerasimenko from ROSINA/DFMS. Implications for nucleus heterogeneity?. Astronomy and Astrophysics - A&A, 2015, 583, A4 (8 p.). ⟨10.1051/0004-6361/201526205⟩. ⟨insu-01206306⟩