Small-N collisional dynamics - II. Roaming the realm of not-so-small-N

Nathan W.C. Leigh, Aaron M. Geller

Research output: Contribution to journalArticlepeer-review

16 Scopus citations


We develop a formalism for calculating probabilities for the outcomes of stellar dynamical interactions, based on results fromN-body scattering experiments. We focus here on encounters involving up to six particles and calculate probabilities for direct stellar collisions; however our method is in principle valid for larger particle numbers. Our method relies on the binomial theorem, and is applicable to encounters involving any combination of particle radii. We further demonstrate that our basemodel is valid to within a fewper cent for any combination of particle masses, provided the minimum mass ratio is within a factor of a few from unity. This method is particularly suitable for models of collisional systems involving large numbers of stars, such as globular clusters, old open clusters and galactic nuclei, where small subsets of stars may regularly have very close encounters, and the direct integration of all such encounters is computationally expensive. Variations of our method may also be used to treat other encounter outcomes, such as ejections and exchanges.

Original languageEnglish (US)
Pages (from-to)1724-1731
Number of pages8
JournalMonthly Notices of the Royal Astronomical Society
Issue number2
StatePublished - Apr 10 2015


  • Binaries: close
  • Globular clusters: general
  • Gravitation
  • Scattering -methods: analytical
  • Stars: kinematics and dynamics

ASJC Scopus subject areas

  • Astronomy and Astrophysics
  • Space and Planetary Science


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