Origin of the variety of asteroids and icy satellites driven by the impact disruption of planetesimals in thermal evolution

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Impact disruption of planetesimals with layered structure in their interiors could be one of the origins of the density and composition variation observed in asteroids and satellites. Thus, we studied the compaction and the sintering processes of icy planetesimals and also studied the impact process of small icy bodies with various porosities originated from the impact disruption of the sintered bodies, so that we clarified the porosity distribution of the planetesimal interiors and the porosity dependence of the impact strength. Furthermore, we also made impact-cratering experiments on the layered surface of the rocky planetesimals and collisional experiments on the rubble-pile bodies. Thus, we clarified that the effects of layered structures on the crater formation and the effects of fragment number and fragment size of the rubble-pile on the impact disruption.