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arXiv 1502.07346astro-ph.EP
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地球和月球之间成分相似性的原始起源

A primordial origin for the composition similarity between the Earth and the Moon

Alessandra Mastrobuono-Battisti, Hagai B. Perets, Sean N. Raymond

摘要:

地月系统的大部分性质都可以用行星胚胎与生长中的地球在吸积过程后期的碰撞来解释。模拟显示,最终聚集形成月球的大部分物质来自撞击物。然而,对地球和月球同位素组成的分析表明它们非常相似。相比之下,其他太阳系天体的组成与地球和月球有很大不同。这对大撞击假设提出了一个重大挑战,因为形成月球的撞击物被认为在成分上也与原始地球不同。在这里,我们在一系列行星吸积的模拟中跟踪生长行星的进食区,以测量形成月球的撞击物的成分。我们发现,在同一模拟中形成的不同行星具有不同的成分,但巨型撞击物的成分在系统上与它们撞击的行星更相似。很大一部分行星撞击物对具有几乎相同的组成。因此,地球和月球在成分上的相似性可能是一次晚期巨大撞击的自然结果。

英文摘要:

Most of the properties of the Earth-Moon system can be explained by a collision between a planetary embryo and the growing Earth late in the accretion process. Simulations show that most of the material that eventually aggregates to form the Moon originates from the impactor. However, analysis of the terrestrial and lunar isotopic composition show them to be highly similar. In contrast, the compositions of other solar system bodies are significantly different than the Earth and Moon. This poses a major challenge to the giant impact scenario since the Moon-forming impactor is then thought to also have differed in composition from the proto-Earth. Here we track the feeding zones of growing planets in a suite of simulations of planetary accretion, in order to measure the composition of Moon-forming impactors. We find that different planets formed in the same simulation have distinct compositions, but the compositions of giant impactors are systematically more similar to the planets they impact. A significant fraction of planet-impactor pairs have virtually identical compositions. Thus, the similarity in composition between the Earth and Moon could be a natural consequence of a late giant impact.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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