We present a series of numerical simulations using a shock physics smoothed particle hydrodynamics code, investigating energetic impacts on small celestial bodies characterized by diverse internal structures, ranging from weak and homogeneous compositions to rubble-pile structures with varying boulder volume packing. Our findings reveal that the internal structure of these rubble-pile bodies significantly influences the impact outcomes. Specifically, we observe that the same impact energy can either catastrophically disrupt a target with a low boulder packing (≲30 vol%), or result in the ejection of only a small fraction of material from a target with the same mass but high boulder packing (≳40 vol%). This finding highlights the pivotal role played by the rubble-pile structure, effectively acting as a bulk shear strength, which governs the size and behavior of the resulting impact. Consequently, understanding and characterizing the internal structure of asteroids will be of paramount importance for any future efforts to deflect or disrupt an asteroid on a collision course with Earth.

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从 NASA DART Impact 破坏碎石堆小行星的经验教训

我们使用冲击物理平滑粒子流体动力学代码进行了一系列数值模拟，研究了对具有不同内部结构特征的小天体的能量影响，从弱且均匀的成分到具有不同巨石体积填充的碎石堆结构。我们的研究结果表明，这些碎石堆体的内部结构对撞击结果有显着影响。具体来说，我们观察到相同的冲击能量要么会灾难性地破坏具有低砾石堆积（≲30 vol%）的目标，要么导致从具有相同质量但高砾石堆积的目标中仅喷射出一小部分材料(≳40 vol%)。这一发现凸显了碎石桩结构所发挥的关键作用，它有效地充当了整体剪切强度，控制着所产生的影响的大小和行为。因此，了解和表征小行星的内部结构对于未来在与地球碰撞过程中偏转或扰乱小行星的任何努力至关重要。