The Fate of Asteroid Ejecta
The Fate of Asteroid Ejecta
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发表时间：
2002-03
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通讯作者：
D. Scheeres;D. Durda;P. Geissler
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作者：
D. Scheeres;D. Durda;P. Geissler
直到最近才通过航天器的现场观测直接测量小行星表面的风化层分布。令许多研究人员感到惊讶的是，大多数关于小行星撞击喷出物分布的经典预测都不正确，小行星表面的风化层似乎在小尺度上具有地质活性。这表明，通过对小行星上撞击喷出物分布情况的详细研究，可以推断出对小行星上地质过程的重要了解。本章的写作旨在支持这些未来的研究，试图识别和澄清此类研究的所有重要要素，指出此类研究的近期历史，并指出目前我们理解中的差距。本章首先讨论小行星表面撞击产生的喷出物场的初始条件。然后回顾了影响小行星轨道和表面抛射物的相关物理规律和力，并阐述了抛射物运动的基本动力学方程。给出了这些方程的解的一些一般结果和约束条件，并给出了喷出物轨迹的分类方案。最后，回顾了最近对小行星喷出物的研究，说明了这些技术在小行星科学中的应用。
The distribution of regolith on asteroid surfaces has only recently been measured directly by in situ observations from spacecraft. To the surprise of many researchers, most of the classical predictions for the distribution of asteroid impact ejecta have not rung true, with regoliths appearing to be geologically active at small scales on asteroid surfaces. This indicates that significant insight into geological processes on asteroids may be inferred by detailed studies of the distribution of impact ejecta on asteroids. This chapter has been written to support these future investigations, by trying to identify and clarify all the important elements for such a study, to point to the recent history of such studies, and to indicate the current gaps in our understanding. The chapter begins with a discussion of the initial conditions of ejecta fields generated from impacts on the asteroid surface. Then the relevant physical laws and forces affecting asteroid ejecta, in orbit and on the surface, are reviewed and the basic dynamical equations of motion for ejecta are stated. Some general results and constraints on the solutions to these equations are given, and a classification scheme for ejecta trajectories is given. Finally, recent studies of asteroid ejecta are reviewed, showing the application of these techniques to asteroid science.