Journal Article

Cometary science. The organic-rich surface of comet 67P/Churyumov-Gerasimenko as seen by VIRTIS/Rosetta

Colangeli, L, Federico, C, Leyrat, C, Markus, K, Barucci, M A, Henry, F, Combe, J-Ph, Erard, S, Politi, R, Peter, G, Filacchione, G, Encrenaz, T, Blanco, A, Cartacci, M, Longobardo, A, Cicchetti, A, Taylor, F, Despan, D, Magni, G, Rinaldi, G, Tozzi, G P, Frigeri, A, Jacquinod, S, Langevin, Y, Mennella, V, McCord, T, Ip, W H, Beck, P, Combi, M, Jaumann, R, Ciarniello, M, Schmitt, B, Semery, A, Benkhoff, J, Orofino, V, De Sanctis, M C, Piccioni, G, Giuppi, S, Blecka, M, Bellucci, G, Flamini, E, Orosei, R, Bockelee-Morvan, D, Palumbo, P, Tiphene, D, Irwin, P, Drossart, P, Crovisier, J, Ammannito, E, Bonal, L, Arnold, G, Cerroni, P, Mottola, S, Carlson, R, Capria, M T, Carsenty, U, Fink, U, Grassi, D, Bibring, J P, Merlin, F, Noschese, R, Biver, N, Fornasier, S, Gudipati, M, Hello, Y, Coradini, A, Stephan, K, Fonti, S, Quirico, E, Reess, J M, Schade, U, Moroz, L, Tosi, F, Raponi, A, Combes, M, Capaccioni, F, Kuehrt, E, Palomba, E

2015

Overview

The VIRTIS (Visible, Infrared and Thermal Imaging Spectrometer) instrument on board the Rosetta spacecraft has provided evidence of carbon-bearing compounds on the nucleus of the comet 67P/Churyumov-Gerasimenko. The very low reflectance of the nucleus (normal albedo of 0.060 ± 0.003 at 0.55 micrometers), the spectral slopes in visible and infrared ranges (5 to 25 and 1.5 to 5% kÅ(-1)), and the broad absorption feature in the 2.9-to-3.6-micrometer range present across the entire illuminated surface are compatible with opaque minerals associated with nonvolatile organic macromolecular materials: a complex mixture of various types of carbon-hydrogen and/or oxygen-hydrogen chemical groups, with little contribution of nitrogen-hydrogen groups. In active areas, the changes in spectral slope and absorption feature width may suggest small amounts of water-ice. However, no ice-rich patches are observed, indicating a generally dehydrated nature for the surface currently illuminated by the Sun.