On the Spatial Homogeneity of the H2O Coma of 67P/C.-G. at 3.9-3.5 AU as Seen from MIRO
Thursday, 18 December 2014
The Rosetta spacecraft reached the Jupiter family comet 67P/C.-G. on 6thAugust, 2014 after a ten year long journey through interstellar space. This mission will provide unique opportunity to study the comet from a near nucleus distance ( < 100 km) with multiple remote and in-situ instruments, including a landing module. One of the scientific goals of this mission is to improve our understanding of cometary activity, and distinguish the primordial features of this object from the process driven features. We use the MIRO instrument measuring the H2O rotational transitions at sub-millimeter wavelengths to investigate the spatial and temporal variability of the early developed gaseous coma. The first successful detection of water by MIRO occurred on June 6-7 2014 at the heliocentric distance of 3.9 AU. However, in this report we also include mapping mode observations to study the coma spatial and time evolution. We apply a robust retrieval approach to constrain H2O number density and expansion velocity.