Open AccessThe evolution of binary fractions in globular clusters
Author(s) -
Ivanova N.,
Belczynski K.,
Fregeau J. M.,
Rasio F. A.
Publication year - 2005
Publication title -
monthly notices of the royal astronomical society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.058
H-Index - 383
eISSN - 1365-2966
pISSN - 0035-8711
DOI - 10.1111/j.1365-2966.2005.08804.x
Subject(s) - globular cluster , physics , binary number , astrophysics , binary star , cluster (spacecraft) , star cluster , population , blue straggler , monte carlo method , statistical physics , stellar evolution , stars , statistics , arithmetic , mathematics , demography , sociology , computer science , programming language
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.