The evolution of binary fractions in globular clusters

N. Ivanova*, K. Belczynski, J. M. Fregeau, F. A. Rasio

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

148 Scopus citations


We study the evolution of binary stars in globular clusters using a new Monte Carlo approach combining a population synthesis code (STARTRACK) and a simple treatment of dynamical interactions in the dense cluster core using a new tool for computing three- and four-body interactions (FEWBODY). We find that the combination of stellar evolution and dynamical interactions (binary-single and binary-binary) leads to a rapid depletion of the binary population in the cluster core. The maximum binary fraction today in the core of a typical dense cluster such as 47 Tuc, assuming an initial binary fraction of 100 per cent, is only ∼5-10 per cent. We show that this is in good agreement with recent Hubble Space Telescope observations of close binaries in the core of 47 Tuc, provided that a realistic distribution of binary periods is used to interpret the results. Our findings also have important consequences for the dynamical modelling of globular clusters, suggesting that 'realistic models' should incorporate much larger initial binary fractions than has usually been the case in the past.

Original languageEnglish (US)
Pages (from-to)572-584
Number of pages13
JournalMonthly Notices of the Royal Astronomical Society
Issue number2
StatePublished - Apr 1 2005


  • Binaries: close
  • Binaries: general
  • Globular clusters: general
  • Globular clusters: individual: NGC 104 (47 Tucanae)
  • Methods: N-body simulations
  • Stellar dynamics

ASJC Scopus subject areas

  • Astronomy and Astrophysics
  • Space and Planetary Science


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