Cratering Experiments on Granular Targets With a Variety of Particle Sizes: Implications for Craters on Rubble‐Pile Asteroids
Cratering Experiments on Granular Targets With a Variety of Particle Sizes: Implications for Craters on Rubble‐Pile Asteroids
复制标题
各种粒径的颗粒目标的陨石坑实验：对碎石堆小行星陨石坑的影响
DOI：
10.1029/2021je007172
复制
发表时间：
2022
期刊：
影响因子：
--
通讯作者：
Hasegawa S.
中科院分区：
文献类型：
--
作者：
Yasui M.;Arakawa M.;Okawa H.;Hasegawa S.
我们对由具有幂律尺寸分布的玻璃珠组成的目标进行了陨石坑实验，模拟了碎石堆小行星的表面，并利用动量传递效率改进了先前研究的陨石坑尺寸缩放关系的折减因子，包括装甲效应。陨石坑实验是使用神户大学和 ISAS/JAXA 的轻气枪进行的，将撞击速度 控制在 50 至 4,400 m s−1 之间。通过混合直径为 0.1、1、3 和 10 毫米的玻璃珠制备了两种混合靶材，一种具有最小直径的玻璃珠，一种没有。目标珠与弹丸（直径 1-3 毫米）的尺寸比从 0.03 变为 10。发现混合目标的弹坑尺寸比例关系取决于第一次接触的珠尺寸。值得注意的是，第一次接触 10 毫米大小的珠子最多可将弹坑半径减少 35%。由于这种装甲效应对弹坑尺寸比例关系的减少因子写如下：随着靶珠与弹丸尺寸比的增大而减小，随着冲击速度的增大而增大，并趋于一致。我们改进的陨石坑大小比例关系（包括折减因子）可用于重建碎石堆小行星（如龙宫）的陨石坑大小频率分布，并且可能导致小行星陨石坑年表的修订。
We performed cratering experiments on targets composed of glass beads with a power‐law size distribution that simulated the surface of rubble‐pile asteroids, and we improved the previously studied reduction factor on the crater size scaling relationship including the armoring effect using the momentum transfer efficiency. Cratering experiments were conducted using light gas guns at Kobe University and ISAS/JAXA to control the impact velocity, , from 50 to 4,400 m s−1. Two kinds of mixed targets were prepared by mixing glass beads with diameters of 0.1, 1, 3, and 10 mm—one with the smallest diameter beads, and one without. The size ratio of the target bead to the projectile (diameter of 1–3 mm), , changed from 0.03 to 10. The crater size scaling relationships for the mixed targets were found to depend on the first contacted bead size. Notably, first contact with a 10 mm‐sized bead reduced the crater radius by 35% in maximum. The reduction factor due to this armoring effect on the crater size scaling relationship is written as follows: ; it decreased with the increase of the size ratio of the target bead to the projectile, while it increased with the increase of the impact velocity and approached unity. Our improved crater size scaling relationship that includes the reduction factor could be used to reconstruct the crater size frequency distribution on rubble‐pile asteroids such as Ryugu, and it may lead to a revision of the crater chronology of asteroids.