Multiple Impact Origin for the Moon

Abstract

The hypothesis of lunar origin by a single giant impact can explain some aspects of the Earth-Moon system. However, it is difficult to reconcile giant impact models with the compositional similarity of the Earth and Moon without violating angular momentum constraints. Furthermore, successful giant impact scenarios require very specific conditions such that they have a low probability of occurring. Here we present numerical simulations suggesting that the Moon could instead be the product of a succession of a variety of smaller collisions. In this scenario, each collision forms a debris disk around the proto-Earth that then accretes to form a moonlet. The moonlets tidally advance outward, and may coalesce to form the Moon. We find that sub-lunar moonlets are a common result of impacts expected onto the proto-Earth in the early solar system and find that the planetary rotation is limited by impact angular momentum drain. We conclude that, assuming efficient merger of moonlets, a multiple impact scenario can account for the formation of the Earth-Moon system with its present properties.

References in corpus (6)

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Cited by in corpus (10)

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• Chaotic quadruple secular evolution and the production of misaligned exomoons and Warm Jupiters in stellar multiples
• Constraints on the pre-impact orbits of Solar System giant impactors
• Dynamical Constraints on Mercury's Collisional Origin
• A Model of the Primordial Lunar Atmosphere
• Modeling a Transient Secondary Paleo-Lunar Atmosphere: 3-D Simulations and Analysis
• Fate of the runner in hit-and-run collisions
• Impact Dynamics of Moons Within a Planetary Potential