The Hayabusa2 mission impact experiment on asteroid Ryugu created an unexpectedly large crater. The associated regime of low-gravity, low-strength cratering remained largely unexplored so far, because these impact conditions cannot be re-created in laboratory experiments on Earth. Here we show that the target cohesion may be very low and the impact probably occurred in the transitional cratering regime, between strength and gravity. For such conditions, our numerical simulations are able to reproduce the outcome of the impact on Ryugu, including the effects of boulders originally located near the impact point. Consistent with most recent analysis of Ryugu and Bennu, cratering scaling-laws derived from our results suggest that surfaces of small asteroids must be very young. However, our results also show that the cratering efficiency can be strongly affected by the presence of a very small amount of cohesion. Consequently, the varying ages of different geological surface units on Ryugu may be due to the influence of cohesion.

Hayabusa2 对小行星 Ryugu 的任务撞击实验造成了一个意想不到的大陨石坑。迄今为止，相关的低重力、低强度陨石坑机制在很大程度上仍未得到探索，因为这些撞击条件无法在地球上的实验室实验中重现。在这里，我们表明目标凝聚力可能非常低，并且影响可能发生在强度和重力之间的过渡陨石坑制度中。对于这种情况，我们的数值模拟能够重现对 Ryugu 的影响结果，包括最初位于撞击点附近的巨石的影响。与最近对 Ryugu 和 Bennu 的分析一致，从我们的结果中得出的陨石坑比例定律表明，小行星的表面一定非常年轻。然而，我们的结果还表明，极少量内聚力的存在会严重影响缩孔效率。因此，Ryugu 上不同地质地表单元的不同年龄可能是由于凝聚力的影响。