Survival of non-coplanar, closely packed planetary systems after a close encounter

David R. Rice*, Frederic A. Rasio, Jason H. Steffen

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

27 Scopus citations


Planetary systems with more than two bodies will experience orbital crossings at a time related to the initial orbital separations of the planets. After a crossing, the system enters a period of chaotic evolution ending in the reshaping of the system's architecture via planetary collisions or ejections. We carry out N-body integrations on a large number of systems with equally spaced planets (in units of the Hill radius) to determine the distribution of instability times for a given planet separation.We investigate both the time to the initiation of instability through a close encounter and the time to a planet-planet collision. We find that a significant portion of systems with non-zero mutual inclinations survive after a close encounter and do not promptly experience a planet-planet collision. Systems with significant inclinations can continue to evolve for over 1000 times longer than the encounter time. The fraction of long-lived systems is dependent on the absolute system scale and the initial inclination of the planets. These results have implications to the assumed stability of observed planetary systems.

Original languageEnglish (US)
Pages (from-to)2205-2212
Number of pages8
JournalMonthly Notices of the Royal Astronomical Society
Issue number2
StatePublished - Dec 1 2018


  • Methods: numerical
  • Planets and satellites: dynamical evolution and stability

ASJC Scopus subject areas

  • Astronomy and Astrophysics
  • Space and Planetary Science


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