论文标题
潮汐失真和重新审视的瓦砾体的破坏 - 软球离散元素分析
Tidal distortion and disruption of rubble-pile bodies revisited -- Soft-sphere discrete element analyses
论文作者
论文摘要
在对行星或恒星的紧密方法中，可以修改碎石毛皮小体的形态和动力学特性，有些可能会灾难性地分解。这种现象是理解小物体的进化和人口以及为将来的相遇做出预测的尤其感兴趣的。以前的数值探索通常使用的方法不充分代表瓦砾桩的性质。相遇结果和影响因素仍然受到限制。根据对瓦砾桩进行建模的最新进展，我们旨在通过软球离散元素建模（SSDEM）更好地了解潮汐遭遇过程，并建立相遇结果的数据库以及对相遇条件和碎石属性属性的依赖性。我们使用N体代码PKDGRAV中实现的SSDEM进行了数千次数值模拟，以研究与地球的紧密相遇期间碎石桩的动态演变。探索了相遇条件，材料强度，排列和组成粒子的分辨率的影响。将三种典型的潮汐遭遇结果分类，即变形，质量脱落和破坏，从轻度修改到祖先的严重损害。引起干扰事件所需的相遇速度和距离要比以前的研究所预测的速度要小得多，这表明潮汐破坏小体群的创造率较小。轴比〜1：6的极度细长片段可以通过中等遇到的形成。我们对最大残余物的自旋形状演变的分析表明，响应潮汐力的瓦砾桩的重塑机制，与Continuum理论得出的稳定的碎石 - 纤维构型一致。 SL9的案例研究表明其祖先的体积密度低（0.2-0.3 g/cc）。
During close approaches to planets or stars, the morphological and dynamical properties of rubble-pile small bodies can be modified, and some may catastrophically break up. This phenomenon is of particular interest for understanding the evolution and population of small bodies, and for making predictions for future encounters. Previous numerical explorations typically used methods that do not adequately represent the nature of rubble piles. The encounter outcomes and influence factors are still poorly constrained. Based on recent advances in modeling rubble piles, we aim to provide a better understanding of the tidal encounter processes through soft-sphere discrete element modeling (SSDEM) and to establish a database of encounter outcomes and the dependencies on encounter conditions and rubble-pile properties. We performed thousands of numerical simulations using the SSDEM implemented in the N-body code pkdgrav to study the dynamical evolution of rubble piles during close encounters with the Earth. The effects of encounter conditions, material strength, arrangement, and resolution of constituent particles are explored. Three typical tidal encounter outcomes are classified, i.e., deformation, mass shedding, and disruption, ranging from mild modifications to severe damages of the progenitor. The encounter speed and distance required for causing disruption events are much smaller than those predicted by previous studies, indicating a smaller creation rate of tidally disrupted small body populations. Extremely elongated fragments with axis ratios ~1:6 can be formed by moderate encounters. Our analyses of the spin-shape evolution of the largest remnants reveal reshaping mechanisms of rubble piles in response to tidal forces, consistent with stable rubble-pile configurations derived by continuum theory. A case study for SL9 suggests a low bulk density (0.2-0.3 g/cc) for its progenitor.
