Hit-and-run planetary collisions

  title={Hit-and-run planetary collisions},
  author={Erik Asphaug and Craig Bruce Agnor and Quentin Williams},
Terrestrial planet formation is believed to have concluded in our Solar System with about 10 million to 100 million years of giant impacts, where hundreds of Moon- to Mars-sized planetary embryos acquired random velocities through gravitational encounters and resonances with one another and with Jupiter. This led to planet-crossing orbits and collisions that produced the four terrestrial planets, the Moon and asteroids. But here we show that colliding planets do not simply merge, as is commonly… 

Similar-sized collisions and the diversity of planets

Signatures of Hit-and-run Collisions

Terrestrial planets grew in a series of similar-sized collisions that swept up most of the next-largest bodies. Theia was accreted by the Earth to form the Moon according to the theory. Planetesimals


The late stages of terrestrial planet formation are dominated by giant impacts that collectively influence the growth, composition, and habitability of any planets that form. Hitherto, numerical

Terrestrial planet formation in extra-solar planetary systems

  • S. Raymond
  • Physics, Geology
    Proceedings of the International Astronomical Union
  • 2007
Abstract Terrestrial planets form in a series of dynamical steps from the solid component of circumstellar disks. First, km-sized planetesimals form likely via a combination of sticky collisions,

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In planetary systems with sufficiently small inter-planet spacing, close encounters can lead to planetary collisions/mergers or ejections. We study the spin property of the merger products of two

Collision Chains among the Terrestrial Planets. III. Formation of the Moon

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Tidal Forces as Drivers of Collisional Evolution

Planetary collisions are usually understood as shock-related phenomena, analogous to impact cratering. But at large scales, where the impact timescale is comparable to the gravitational timescale,

Accretion Efficiency during Planetary Collisions

We present the results of smoothed particle hydrodynamic simulations of collisions between two 0.10 M⊕ differentiated planetary embryos with impact dynamics that are thought to be common to the late

On the Character and Consequences of Large Impacts in the Late Stage of Terrestrial Planet Formation

Abstract We perform three-dimensional N-body integrations of the final stages of terrestrial planet formation. We report the results of 10 simulations beginning with 22–50 initial planetary embryos

Occurrence of Giant Impacts During the Growth of the Terrestrial Planets

Three-dimensional Monte Carlo simulations of the accumulation of the terrestrial planets in the absence of gas drag produced results that are in general agreement with the number and distribution of

Origin of the Moon in a giant impact near the end of the Earth's formation

This work reports a class of impacts that yield an iron-poor Moon, as well as the current masses and angular momentum of the Earth–Moon system, and suggests that the Moon formed near the very end of Earth's accumulation.

Accretional Evolution of a Planetesimal Swarm

We use our multi-zone simulation code (D. Spaute, S. Weidenschilling, D. R. Davis, and F. Marzari,Icarus92,147–164, 1991) to model numerically the accretion of a swarm of planetesimals in the region

Dynamics of Lunar Formation

▪ Abstract The giant impact theory is the leading hypothesis for the origin of the Moon. This review focuses on dynamical aspects of an impact-induced lunar formation, in particular those areas that