Impacts may provide heat for aqueous alteration and organic solid formation on asteroid parent bodies
Impacts may provide heat for aqueous alteration and organic solid formation on asteroid parent bodies
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撞击可能为小行星母体上的水蚀变和有机固体形成提供热量
DOI：
10.1038/s43247-021-00159-x
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发表时间：
2021
期刊：
影响因子：
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通讯作者：
Ogawa Kazunori
中科院分区：
文献类型：
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作者：
Yasui Minami;Tazawa Taku;Hashimoto Ryohei;Arakawa Masahiko;Ogawa Kazunori
小行星母体上的化学反应，如水蚀变和有机固体的形成，都需要热源。这些天体内部的放射性衰变通常被认为是最重要的热源，但撞击产生的加热也可能起作用。本文采用嵌入目标材料的热电偶进行高速撞击实验，直接测量每次撞击实验过程中温度的时空演变。我们发现，陨石坑底部以下的最高温度与距离撞击点的距离成正比，而温度上升的持续时间与热扩散时间成正比。我们使用数值模拟表明，在2个天文单位的距离内，产生半径为100 - 20公里的陨石坑的撞击可以促进陨石坑下方物质的含水蚀变，而产生半径为1公里的陨石坑的撞击可以支持有机固体的形成。
Chemical reactions on asteroid parent bodies, such as aqueous alteration and the formation of organic solids, require a heat source. Radioactive decay in the interiors of these bodies is generally considered the most important heat source, but impact-generated heating is also likely to play a role. Here we present high-velocity impact cratering experiments using thermocouples embedded in the target material to directly measure the spatial and temporal evolution of temperature throughout each impact experiment. We find that the maximum temperature below the crater floor scales with the distance from the impact point, while the duration of temperature rise is scaled by the thermal diffusion time. We use numerical modelling to suggest that, at distances within 2 astronomical units, impacts producing craters of >20 km radius can facilitate aqueous alteration in the material below the crater, while those which produce craters of 1 km radius can support organic solid formation.