Fate of the Runner in Hit-and-run Collisions

Alexandre Emsenhuber, Erik Asphaug

Research output: Contribution to journalArticlepeer-review

18 Scopus citations


In similar-sized planetary collisions, a significant part of the impactor often misses the target and continues downrange. We follow the dynamical evolution of "runners" from giant impacts to determine their ultimate fate. Surprisingly, runners reimpact their target planets only about half of the time for realistic collisional and dynamical scenarios. Otherwise, they remain in orbit for tens of millions of years (the limit of our N-body calculations) and longer, or they sometimes collide with a different planet than the first one. When the runner does return to collide again with the same target planet, its impact velocity is mainly constrained by the outcome of the prior collision. Impact angle and orientation, however, are unconstrained by the prior collision.

Original languageEnglish (US)
Article number95
JournalAstrophysical Journal
Issue number2
StatePublished - Apr 20 2019


  • planets and satellites: formation
  • planets and satellites: terrestrial planets

ASJC Scopus subject areas

  • Astronomy and Astrophysics
  • Space and Planetary Science


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