Temporal morphological changes at the surface of comet 67P/Churyumov-Gerasimenko
Résumé
A key scientific question, to understand how comets work and whether they still contain pristine materials at or near their surface, is to understand how the nucleus is changing with time and to which extent activity modifies its surface. Rosetta, which has been orbiting comet 67P/Churyumov-Gerasimenko since August 2014, offers a unique opportunity to tackle this fundamental question. Here, we report on temporal morphological changes detected on the surface of the nucleus of comet 67P by the OSIRIS cameras. Changes have been detected in several regions and in particular in the Imhotep region, where they are visible in the form of roundish features that are growing in size from a given location in a preferential direction. Terrains bluer than the surroundings appear during changes, suggesting the presence of (water) ice exposed on the surface.