The rocky‐like behavior of cometary landslides on 67P/Churyumov‐Gerasimenko

Abstract : Landslides have been identified on several Solar System bodies and different mechanisms have been proposed to explain their runout length. We analyse images from the Rosetta mission and report the global characterisation of such features on comet 67P/Churyumov‐Gerasimenko's surface. By assuming the height to runout length as an approximation for the friction coefficient of landslide material, we find that on comet 67P, this ratio falls between 0.50 and 0.97. Such unexpected high values reveal a rocky‐type mechanical behaviour that is much more akin to Earth dry landslides than to icy satellites' mass movements. This behaviour indicates that 67P and likely comets in general are characterised by consolidated materials possibly rejecting the idea that they are fluffy aggregates. The variability of the runout length among 67P landslides can be attributed to the different volatile content located in the top few meters of the cometary crust, which can drive the mass movement.