VIRTIS on Rosetta: a unique technique to observe comet 67P/Churyumov-Gerasimenko - first results and prospects

Abstract

VIRTIS aboard ESA’s Rosetta mission is a complex imaging spectrometer that combines three unique data channels in one compact instrument to study nucleus and coma of comet 67P/Churyumov-Gerasimenko. Two of the spectral channels are dedicated to spectral mapping (-M) at moderate spectral resolution in the range from 0.25 to 5.1 μm. The third channel is devoted to high resolution spectroscopy (-H) between 2 and 5 μm. The VIRTIS-H field of view is approximately centered in the middle of the -M image. The spectral sampling of VIRTIS-M is 1.8 nm/band below 1 μm and 9.7 nm/band between 1-5 μm, while for VIRTIS-H λ/Δλ= 1300-3000 in the 2-5 μm range. This paper describes selected findings during the pre-landing phase of Philae’s robotic subsystem and the comet’s escort phase as well as prospects of further observations. The preliminary results include studies of surface composition, coma analyses, and temperature retrieval for the nucleus surface-coma system demonstrating the capability of the instrument.