发表机构
Chiba University; Nagoya University（千叶大学; 名古屋大学）
机构由 AI 辅助整理，请以论文原文为准。AI 中文总结
本研究采用物质点法模拟等质量低速小行星碰撞，与SPH结果对比验证其适用性，表明MPM能有效重现碰撞产物的形状与质量趋势，支持两种方法的交叉验证。
AI 中文摘要
在当今主带中，直径大于约10公里的小行星的碰撞寿命估计超过太阳系的年龄，这表明它们的形状可能保存了原始太阳系中碰撞环境的记忆。近期研究使用光滑粒子流体动力学（SPH）对半径50公里的小行星进行了等质量和低速（50–400米/秒）碰撞的系统模拟，识别出产生不规则形状的撞击条件。作为一种替代方法，我们在此采用物质点法（MPM），这是一种适用于固体大变形且无拉伸不稳定性的粒子-网格方法，并通过与已建立的SPH结果直接比较来评估其对此类系统的适用性。我们整合了先前建立的岩石模型与断裂模型、Tillotson状态方程和Drucker-Prager摩擦，以及最初为颗粒流开发的高效非关联Drucker-Prager塑性求解器。我们按照先前SPH模拟的设置，进行了135次等质量岩石小行星的碰撞模拟，涵盖15种撞击速度（50–400米/秒）和9种撞击角度（5–45°）。最大残余体的质量、轴比和形状分类与先前SPH模拟的趋势高度吻合。由于大多数物质在碰撞早期转变为颗粒状态，这种一致性似乎主要依赖于颗粒材料摩擦处理的有效性，而非断裂模型的细节。这些结果证明了MPM在低速小行星碰撞模拟中的适用性，并支持基于MPM和SPH的方法之间的交叉验证。
英文摘要
The collisional lifetimes of asteroids larger than $\sim 10$ km in the present-day main belt are estimated to exceed the age of the solar system, suggesting that their shapes may preserve memories of the collisional environment in the primordial solar system. Recent studies performed systematic simulations of equal-mass and low-velocity ($50$--$400\,\mathrm{ms}^{-1}$) collisions between 50-km-radius asteroids using Smoothed Particle Hydrodynamics (SPH), identifying the impact conditions that produce irregular shapes. As an alternative approach, we here employ the Material Point Method (MPM), a particle-grid method well suited to large deformation of solids and free from tensile instability, and we assess its applicability to such systems by direct comparison with the established SPH results. We integrate a previously established rock model combined with a fracture model, the Tillotson equation of state, and Drucker-Prager friction, with the efficient non-associative Drucker-Prager plasticity solver originally developed for granular flows. We perform 135 collision simulations of equal-mass rocky asteroids spanning 15 impact velocities ($50$--$400\,\mathrm{ms}^{-1}$) and 9 impact angles ($5$--$45^\circ$), following the setup of the previous SPH simulations. The mass, axis ratio, and shape classification of the largest remnants closely reproduce the trends of the previous SPH simulations. Since most material transitions into a granular state early in the collision, this agreement appears to depend primarily on the validity of the frictional treatment of the granular material, rather than on the details of the fracture model. These results demonstrate the applicability of MPM to low-velocity asteroid collision simulations and support cross-validation between MPM- and SPH-based approaches.
Comments10 pages, 4 figures, submitted to ApJL
