Distant Coma Composition of Comet 67P/Churyumov-Gerasimenko as Observed from Rosetta/VIRTIS

Abstract:

Since July 2014, the Visual IR Thermal Imaging Spectrometer (VIRTIS) onboard the ESA’s Rosetta spacecraft has intensively observed comet 67P/ Churyumov-Gerasimenko. VIRTIS is composed of two channels, –M for mapping and –H for high resolution, working in the 0.25-5 μm and 2-5 μm wavelength domains, respectively. In addition to nucleus mapping observations, limb observations were carried out to obtain spectra of the coma, and to detect fluorescence emissions of gas phase species. In particular, H₂O, CO₂, CO and organics have strong vibrational bands in the 2.5-5 μm range. We will present VIRTIS-H and M spectra of the coma obtained when 67P was at heliocentric distances larger than 2.8 AU and their analysis.

The authors acknowledge funding from French and Italian Space Agencies.