Size of particles ejected from an artificial impact crater on asteroid 162173 Ryugu

A projectile accelerated by the Hayabusa2 Small Carry-on Impactor successfully produced an artificial impact crater with a final apparent diameter of 14.5 ± 0.8 m on surface near-Earth asteroid 162173 Ryugu April 5, 2019. At time cratering, Deployable Camera 3 took clear time-lapse images ejecta curtain, assemblage ejected particles forming curtain-like structure emerging from crater. Focusing optical depth curtain and comparing it theoretical model, we infer size particles. As result, typical is estimated to be several centimeters decimeters, although slightly depends assumed distribution. Since are expected come down ~1 m, our result suggests that subsurface layer composed relatively small compared uppermost which observe many meter-sized boulders. Our also deficit less than mm in layer. These findings will play key role revealing formation evolution process other Solar System bodies.