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arXiv 1802.03356astro-ph.EP
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月球从高密度、高angular-momentum地球的潮汐演化

Tidal evolution of the Moon from a high-obliquity, high-angular-momentum Earth

Matija Ćuk, Douglas P. Hamilton, Simon J. Lock, Sarah T. Stewart

摘要:

在月球起源的巨大撞击假说中,月球是从赤道环地圆盘吸积而来;然而,目前月球轨道倾角为5度,需要一个后续的动力学过程,这一过程仍有争议。此外,巨大撞击理论也受到月球与地球相似的同位素组成的挑战。在这里,我们表明,潮汐耗散由于月球的潮汐演化过程中的一个重要影响,过去的月球倾角必须是非常大的,无视理论解释。我们提出了一个新的潮汐演化模型,从月球在赤道轨道上围绕一个最初快速旋转,高密度的地球,这是一个可能的结果巨大的影响。利用数值模拟,我们表明,太阳对月球轨道的扰动自然会引起一个大的月球倾角,并从地月系统中删除角动量。我们的潮汐演化模型支持最近的高角动量巨型撞击情景,以解释月球的同位素组成,并提供了一条新的途径,以达到地球的气候有利的低盐度。

英文摘要:

In the giant impact hypothesis for lunar origin, the Moon accreted from an equatorial circum-terrestrial disk; however the current lunar orbital inclination of 5 degrees requires a subsequent dynamical process that is still debated. In addition, the giant impact theory has been challenged by the Moon's unexpectedly Earth-like isotopic composition. Here, we show that tidal dissipation due to lunar obliquity was an important effect during the Moon's tidal evolution, and the past lunar inclination must have been very large, defying theoretical explanations. We present a new tidal evolution model starting with the Moon in an equatorial orbit around an initially fast-spinning, high-obliquity Earth, which is a probable outcome of giant impacts. Using numerical modeling, we show that the solar perturbations on the Moon's orbit naturally induce a large lunar inclination and remove angular momentum from the Earth-Moon system. Our tidal evolution model supports recent high-angular momentum giant impact scenarios to explain the Moon's isotopic composition and provides a new pathway to reach Earth's climatically favorable low obliquity.

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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