SPH simulations for shape deformation of rubble-pile asteroids through spinup: The challenge for making top-shaped asteroids Ryugu and Bennu
SPH simulations for shape deformation of rubble-pile asteroids through spinup: The challenge for making top-shaped asteroids Ryugu and Bennu
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DOI：
10.1016/j.icarus.2021.114505
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发表时间：
2021-04-28
期刊：
影响因子：
3.2
通讯作者：
Inutsuka, Shu-ichiro
中科院分区：
文献类型：
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作者：
Sugiura, Keisuke;Kobayashi, Hiroshi;Inutsuka, Shu-ichiro
小行星162173 Ryugu和小行星101955 Bennu最近分别被Hayabusa 2和OSIRIS-REx探测器访问，它们正在旋转顶部形状的碎石堆。其他轴对称的顶部形状的近地小行星已经被地面雷达观测到，其中大多数旋转接近分裂旋转周期类似于3小时。这表明，通过旋转自旋引起的小行星变形产生了顶部形状。尽管之前使用离散元方法进行的一些模拟表明，碎石堆的旋转可能会产生扁圆形顶部形状，但目前尚不清楚顶部形状形成需要哪些条件，例如组成材料的摩擦角和旋转时间尺度。通过对不同速率旋转颗粒体的光滑粒子流体动力学模拟，发现球形碎石堆在破碎前的旋转变形可以根据摩擦角φ（d）分为三种模式：准静态和内部变形（φ（d））
Asteroid 162173 Ryugu and asteroid 101955 Bennu, which were recently visited by spacecraft Hayabusa2 and OSIRIS-REx, respectively, are spinning top-shaped rubble piles. Other axisymmetric top-shaped near-Earth asteroids have been observed with ground-based radar, most of which rotate near breakup rotation periods of similar to 3 h. This suggests that rotation-induced deformation of asteroids through rotational spinup produces top shapes. Although some previous simulations using the Discrete Element Method showed that spinup of rubble piles may produce oblate top shapes, it is still unclear what kinds of conditions such as friction angles of constituent materials and spinup timescales are required for top-shape formation. Here we show, through Smoothed Particle Hydrodynamics simulations of granular bodies spinning-up at different rates, that the rotation-induced deformation of spherical rubble piles before breakup can be classified into three modes according to the friction angle phi(d) : quasi-static and internal deformation for phi(d)