Abstrakt
Asteroid crater retention ages have unknown accuracy because projectile-crater scaling laws are difficult to verify. At the same time, our knowledge of asteroid and crater size-frequency distributions has increased substantially over the past few decades.
These advances make it possible to empirically derive asteroid crater scaling laws by fitting model asteroid size distributions to crater size distributions from asteroids observed by spacecraft. ForD > 10 km diameter asteroids like Ceres, Vesta, Lutetia, Mathilde, Ida, Eros, and Gaspra, the best matches occur when the ratio of crater to projectile sizes isf similar to 10.
The same scaling law applied to 0.3 D > 10, which would make their crater retention ages much younger. If true, crater scaling laws need to change in a substantial way betweenD > 10 km asteroids, wheref similar to 10, and 0.3 D > 10.