Cratering efficiency on coarse-grain targets: Implications for the dynamical evolution of asteroid 25143 Itokawa

摘要

Highlights?Cratering experiments on coarse-grained targets are performed.?A new crater size scaling on coarse-grained targets is derived.?Projectile size and impact energy contribute to change in cratering mode.?The crater retention age of Itokawa is estimated to be 3–33?Myr.?The crater age of Itokawa suggests a recent global resurfacing in the main belt.AbstractRemote sensing observations made by the spacecraft Hayabusa provided the first direct evidence of a rubble-pile asteroid: 25143 Itokawa. Itokawa was found to have a surface structure very different from other explored asteroids; covered with coarse pebbles and boulders ranging at least from cm to meter size. The cumulative size distribution of small circular depressions on Itokawa, most of w