Low surface strength of the asteroid Bennu inferred from impact ejecta deposit
Low surface strength of the asteroid Bennu inferred from impact ejecta deposit
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DOI：
10.1038/s41561-022-00937-y
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发表时间：
2022-05-23
影响因子：
18.3
通讯作者：
Lauretta, D. S.
中科院分区：
文献类型：
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作者：
Perry, M. E.;Barnouin, O. S.;Lauretta, D. S.
对与碎石堆小行星Bennu上的一个陨石坑有关的沉积物进行的观测表明，该小行星的表面强度低，很容易因撞击过程而重新形成，小型碎石堆小行星是微重力下未固结物质的集合体，其表面强度不受限制，但对了解该小行星的表面演变和地质历史至关重要。在这里，我们使用的影响喷出物存款和下坡雪崩附近的碎石堆小行星（101955）Bennu的一个70米直径的撞击坑的图像来约束小行星的表面属性。我们推断，火山口附近沉积的喷出物必须以低于Bennu逃逸速度（20 cm s（-1））的速度移动;只有当局部表面的有效强度非常低时，才能解释这种低速度，名义上
Observations of deposits associated with a crater on the rubble-pile asteroid Bennu indicate a surface with low strength that is readily reworked by impact processes.The surface strength of small rubble-pile asteroids, which are aggregates of unconsolidated material under microgravity, is poorly constrained but critical to understanding surface evolution and geologic history of the asteroid. Here we use images of an impact ejecta deposit and downslope avalanche adjacent to a 70-m-diameter impact crater on the rubble-pile asteroid (101955) Bennu to constrain the asteroid's surface properties. We infer that the ejecta deposited near the crater must have been mobilized with velocities less than Bennu's escape velocity (20 cm s(-1)); such low velocities can be explained only if the effective strength of the local surface is exceedingly low, nominally