2005MNRAS.358..572I

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.