Geomorphology of Active Regions on Comet 67P/Churyumov-Gerasimenko from Osiris Observations

Thursday, 18 December 2014
Anne-Thérèse Auger1,2, Olivier Groussin1, Laurent Jorda1, Sylvain Bouley2, Philippe L Lamy1, Gabriele Cremonese3, Nicolas Thomas4 and Holger Sierks5, (1)Laboratoire d'Astrophysique de Marseille, Marseille, France, (2)Laboratoire GEOPS, Orsay, France, (3)INAF - Astronomical Observatory of Padova, Padova, Italy, (4)University of Bern, Bern, Switzerland, (5)Max Planck Institute for Solar System Research, Katlenburg-Lindau, Germany
The geomorphological study of active regions on comets provides valuable insights to understand how comets work and to which extend they may still contain pristine materials on or close to their surface. The Rosetta spacecraft is orbiting comet 67P/Churyumov-Gerasimenko since summer 2014 and offers a unique opportunity to address this science topic. The Narrow and Wide Angle Cameras of the OSIRIS imaging experiment have acquired numerous images of the nucleus surface, with a spatial resolution down to the meter scale. Here, we focus on the geomorphology of some specific, active, regions of the nucleus, releasing materials from their surface or from their upper layers. With the help of digital terrains models and GIS tools, we map these regions and report their size, area, shape, slopes and surface roughness. This detailed analysis give us a reference point to emphasize their evolution as the comet approaches perihelion, but also provide information on the possibly pristine nature of these morphologies.