Q-type asteroids: Possibility of non-fresh weathered surfaces
Q-type asteroids: Possibility of non-fresh weathered surfaces
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Q型小行星：非新鲜风化表面的可能性
DOI：
10.1093/pasj/psz088
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发表时间：
2019
影响因子：
2.3
通讯作者：
S.
中科院分区：
文献类型：
--
作者：
Hasegawa;S.;Hiroi;T.;Ohtsuka;K.;Ishiguro;M.;Kuroda;D.;Ito;T.;Sasaki;S.
丝川粒子是隼鸟号航天器从S-复合小行星25143丝川回收的样品，表明S-复合小行星是普通球粒陨石的母体。此外，他们澄清，Itokawa表面的空间风化年龄是几千年的顺序。传统上，Q-型小行星被认为是表面新鲜的。然而，由于空间风化的时间尺度比通常认为的年龄小大约三个数量级，以前提出的Q-型小行星的形成机制不能充分解释表面的翻新。在这项研究中，我们提出了一个新的假设的表面状态的Q型小行星：Q型小行星有一个非新鲜的风化表面的细小颗粒的缺乏。为了验证这一假设，进行了普通花岗岩的空间风化实验。基于这些实验的结果，我们发现，大的（比）普通的陨石粒子与空间风化表现出光谱一致的Q-型小行星。
Itokawa particles, which are samples recovered from the S-complex asteroid 25143 Itokawa by the Hayabusa spacecraft, demonstrate that S-complex asteroids are parent bodies of ordinary chondrite meteorites. Furthermore, they clarify that the space-weathering age of the Itokawa surface is of the order of several thousand years. Traditionally, Q-type asteroids have been considered fresh-surfaced. However, as the space-weathering timescale is approximately three orders of magnitude lesser than the conventionally considered age, the previously proposed formation mechanisms of Q-type asteroids cannot sufficiently explain the surface refreshening. In this study, we propose a new hypothesis on the surface state of Q-type asteroids: Q-type asteroids have a non-fresh weathered surface with a paucity of fine particles. For verifying this hypothesis, laboratory experiments on the space weathering of ordinary chondrites are performed. Based on the results of these experiments, we found that large (more than) ordinary chondritic particles with space weathering exhibit spectra consistent with Q-type asteroids.