The highly active Anhur–Bes regions in the 67P/Churyumov–Gerasimenko comet: results from OSIRIS/ROSETTA observations
Fornasier, S. and Feller, C. and Lee, J.-C. and Ferrari, S. and Massironi, M. and Hasselmann, P.H. and Deshapriya, J.D.P. and Barucci, M.A. and El-Maarry, Mohamed Ramy and Giacomini, L. and Mottola, S. and Keller, H.U. and Ip, W.-H. and Lin, Z.-Y. and Sierks, H. and Barbieri, C. and Lamy, P.L. and Rodrigo, R. and Koschny, D. and Rickman, H. and Agarwal, J. and A'Hearn, M. and Bertaux, J.-L. and Bertini, I. and Cremonese, G. and Da Deppo, V. and Davidsson, B. and Debei, S. and De Cecco, M. and Deller, J. and Fulle, M. and Groussin, O. and Gutierrez, P.J. and Güttler, C. and Hofmann, M. and Hviid, S.F. and Jorda, L. and Knollenberg, J. and Kovacs, G. and Kramm, R. and Kührt, E. and Küppers, M. and Lara, M.L. and Lazzarin, M. and Lopez Moreno, J.J. and Marzari, F. and Naletto, G. and Oklay, N. and Pajola, M. and Shi, X. and Thomas, N. and Toth, I. and Tubiana, C. and Vincent, J.-B. (2017) The highly active Anhur–Bes regions in the 67P/Churyumov–Gerasimenko comet: results from OSIRIS/ROSETTA observations. Monthly Notices of the Royal Astronomical Society 469 (Suppl_), S93-S107. ISSN 0035-8711.
Abstract
The Southern hemisphere of the 67P/Churyumov–Gerasimenko comet has become visible from Rosetta only since 2015 March. It was illuminated during the perihelion passage and therefore it contains the regions that experienced the strongest heating and erosion rates, thus exposing the sub-surface most pristine material. In this work we investigate, thanks to the OSIRIS images, the geomorphology, the spectrophotometry and some transient events of two Southern hemisphere regions: Anhur and part of Bes. Bes is dominated by outcropping consolidated terrain covered with fine particle deposits, while Anhur appears strongly eroded with elongated canyon-like structures, scarp retreats, different kinds of deposits and degraded sequences of strata indicating a pervasive layering. We discovered a new 140 m long and 10 m high scarp formed in the Anhur–Bes boundary during/after the perihelion passage, close to the area where exposed CO2 and H2O ices were previously detected. Several jets have been observed originating from these regions, including the strong perihelion outburst, an active pit and a faint optically thick dust plume. We identify several areas with a relatively bluer slope (i.e. a lower spectral slope value) than their surroundings, indicating a surface composition enriched with some water ice. These spectrally bluer areas are observed especially in talus and gravitational accumulation deposits where freshly exposed material had fallen from nearby scarps and cliffs. The investigated regions become spectrally redder beyond 2 au outbound when the dust mantle became thicker, masking the underlying ice-rich layers.
Metadata
| Item Type: | Article |
|---|---|
| Keyword(s) / Subject(s): | methods: data analysis, methods: observational, techniques: photometric, comets: individual: 67P/Churyumov–Gerasimenko |
| School: | Birkbeck Faculties and Schools > Faculty of Science > School of Natural Sciences |
| Depositing User: | Administrator |
| Date Deposited: | 17 Oct 2018 17:15 |
| Last Modified: | 02 Aug 2023 17:45 |
| URI: | https://eprints.bbk.ac.uk/id/eprint/24739 |
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