An ongoing satellite-ring cycle of Mars and the origins of Phobos and Deimos
An ongoing satellite-ring cycle of Mars and the origins of Phobos and Deimos
复制标题
火星正在进行的卫星环周期以及火卫一和火卫二的起源
DOI：
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发表时间：
2017
期刊：
影响因子：
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通讯作者：
D. Minton
中科院分区：
文献类型：
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作者：
Andrew J. Hesselbrock;D. Minton
火星卫星火卫一和火卫二可能是从一个撞击碎片环中吸积而成的，但事实证明，要解释它们来自一次巨大的撞击是很困难的。一个线索可能在于火卫一的轨道，当卫星与火星发生潮汐相互作用时，它正在慢慢衰减。在大约7000万年的时间里，火卫一预计将到达潮汐分裂的位置，并在行星周围形成一个新的环。在这里，我们使用数值模拟表明，由此产生的环将粘性蔓延，最终约存款80%的碎片到火星上，其余20%的碎片将吸积成新一代的卫星。此外，我们认为这一过程在火星历史上反复发生。在我们的模拟中，从一颗与早期火星发生巨大撞击后形成的大型卫星开始，我们发现在过去43亿年中，三到七个环卫星周期可以解释火卫一和火卫二今天所观察到的情况。这种情况意味着在每个周期中，大量的环物质沉积在火星上。我们推测，在火星上观察到的一些异常沉积物可能与这些周期性的环沉积有关。火卫一的卫星正在向内旋转，最终在火星周围形成一个新的卫星可能形成的环。模拟表明，这只是火星历史上多次环月周期中最新的一次。
The Martian moons Phobos and Deimos may have accreted from a ring of impact debris, but explaining their origin from a single giant impact has proven difficult. One clue may lie in the orbit of Phobos that is slowly decaying as the satellite undergoes tidal interactions with Mars. In about 70 million years, Phobos is predicted to reach the location of tidal breakup and break apart to form a new ring around the planet. Here we use numerical simulations to suggest that the resulting ring will viscously spread to eventually deposit about 80% of debris onto Mars; the remaining 20% of debris will accrete into a new generation of satellites. Furthermore, we propose that this process has occurred repeatedly throughout Martian history. In our simulations, beginning with a large satellite formed after a giant impact with early Mars, we find that between three and seven ring–satellite cycles over the past 4.3 billion years can explain Phobos and Deimos as they are observed today. Such a scenario implies the deposition of significant ring material onto Mars during each cycle. We hypothesize that some anomalous sedimentary deposits observed on Mars may be linked to these periodic episodes of ring deposition. The moon Phobos is spiralling inwards towards its disintegration to eventually form a ring around Mars from which new moons may form. Simulations suggest that this is just the latest of multiple ring–moon cycles over the history of Mars.