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Landslides on comets

Presentation #218.07 in the session Comets: Coma, Nucleus, Dynamics (Oral Presentation)

Published onOct 23, 2023
Landslides on comets

The stability of the cometary dust mantle may have strong influence on the activity of comets. We investigated conditions for the occurrence of the events of landslides on the surfaces of potential cometary analogs. For this purpose we performed series of experiments using samples composed of porous aggregates of water ice grains, quartz sand and charcoal. Their surfaces were initially free of sand. The experiments were performed in laboratory, where the gravitational acceleration is likely five orders of magnitude higher than on the surface of a comet. Thus, we used sublillimeter grains of sand instead of fine dust. This way we reduced the force of cohesion per unit of volume of the material and made it negligible when compared to the gravitational force. On a small comet containing fine dust the force of cohesion per unit of volume should be similar to the force of gravity per unit of volume under laboratory conditions. Thus, the results of our experiments can be representative for small comets. We have found, that in special conditions the sand may slide down the surface almost the whole time. Hence, the surface can remain free of sand. The results of the experiments were compared to the observations of scarps on the nucleus of comet 67P/Churyumov-Gerasimenko.

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