An asteroid’s interior dictates how its space environment changes its shape and surface, which provides a record of the collisional and dynamical evolution of the Solar System. Knowledge of asteroid interiors also enables the formulation of mitigation strategies against hazardous asteroids. Despite this importance, asteroid interiors remain poorly understood. Asteroids between 0.2 km and 10 km in diameter are thought to have rubble-pile interiors, transitioning to fractured interiors at 10 km scales, then to coherent and differentiated interiors at ≳100 km scales. The asteroid 433 Eros, the only 10-km-scale asteroid explored by a rendezvous mission, is an exemplar of asteroids at intermediate scales. Recent exploration of smaller rubble piles has provided insight into physical properties that are shared with Eros-sized objects. Here we quantify the seismic and physical properties of Eros’ interior through measurements and modelling of crater degradation and erasure from the impact that formed the 7.5-km-diameter Shoemaker crater on Eros. Our results indicate that Eros’ deep interior has a seismic wave scattering length of 0.5 ± 0.1 km and effective quality factor ^EQ < \({63}_{-13}^{+18}\) at frequencies >0.06 Hz. Contrary to the established view of Eros as a fractured shard, our findings suggest that Eros’ interior properties are consistent with those of a rubble-pile asteroid.

小行星的内部决定了其太空环境如何改变其形状和表面，这提供了太阳系碰撞和动力学演变的记录。了解小行星内部还有助于制定针对危险小行星的缓解策略。尽管如此重要，但人们对小行星内部仍然知之甚少。直径在 0.2 公里到 10 公里之间的小行星被认为具有碎石堆内部，在 10 公里尺度上过渡到断裂的内部，然后在 ≳100 公里尺度上过渡到连贯和差异化的内部。小行星 433 Eros 是交会任务探索的唯一一颗 10 公里比例的小行星，是中等比例小行星的典范。最近对较小碎石堆的探索提供了对与 Eros 大小物体共享的物理特性的见解。在这里，我们通过测量和模拟形成 Eros 上直径 7.5 公里的 Shoemaker 陨石坑的撞击造成的陨石坑退化和擦除，量化了 Eros 内部的地震和物理特性。我们的结果表明，爱神星的深层内部具有 0.5 ± 0.1 公里的地震波散射长度，在频率 >0.06 Hz 下有效品质因子 ^EQ < \（{63}_{-13}^{+18}\） 。与将爱神星视为断裂碎片的既定观点相反，我们的研究结果表明，爱神星的内部特性与碎石堆小行星的内部特性一致。