The evolution of binary fractions in globular clusters

By Natalia Ivanova, Krzysztof Belczyński, John Fregeau, F. Rasio. 2005

151 citations recorded by the source corpus.

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 3-body and 4-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 like 47 Tuc, assuming an initial binary fraction of 100%, is only about 5–10%. We show that this is in good agreement with recent HST 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 modeling of globular clusters, suggesting that “realistic models” should incorporate much larger initial binary fractions than has usually been done in the past.

Subfields: Astronomy and Astrophysics

View Paper: https://www.semanticscholar.org/paper/5d9109d824b3dcf9b9d93e72e43bd4ca5867154e

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Citations in the corpus

THE FORMATION OF ECCENTRIC COMPACT BINARY INSPIRALS AND THE ROLE OF GRAVITATIONAL WAVE EMISSION IN BINARY–SINGLE STELLAR ENCOUNTERS (2013, background): “…of the coevolution of binaries and their parent clusters over the cluster’s relaxation time (e.g. Aarseth & Lecar 1975; Hills 1975a,b; Heggie 1975; Lightman & Shapiro 1978; McMillan 1986; Baumgardt et al. 2002; Fregeau et al. 2003; Ivanova et al. 2005a; Fregeau & Rasio 2007; Fregeau et al. 2009).”
The Close Binary Fraction of Solar-type Stars Is Strongly Anticorrelated with Metallicity (2018, result): “Although the binary fraction in dense globular clusters has significantly evolved due to dynamical interactions, the initial close binary fraction of metal-poor solar-type stars in globular clusters must have been large, consistent with the results of N-body simulations (Ivanova et al. 2005).”
A Deep Chandra Survey of the Globular Cluster 47 Tucanae: Catalog of Point Sources (2005, unknown): “Various attempts to derive the fraction of stars in binaries in 47 Tuc have given results from 10%–18% (Albrow et al. 2001, hereafter A01) to P5% (Anderson 1997; Ivanova et al. 2005a).”
Eccentric Black Hole Mergers in Dense Star Clusters: The Role of Binary–Binary Encounters (2018, methodology): “The GC models in this study use an initial binary fraction of 5%, which is loosely based on the observed binary fraction of Milky Way GCs (Rubenstein & Bailyn 1997; Bellazzini et al. 2002; Ivanova et al. 2005).”
THE QUENCHING OF THE ULTRA-FAINT DWARF GALAXIES IN THE REIONIZATION ERA (2014, background): “…(e.g., Duquennoy & Mayor QUENCHING OF THEULTRA-FAINT DWARF GALAXIES 7 1991), the UFDs have a binary fraction of nearly 50% (Geha et al. 2013) – much higher than the binary fraction in M92 (∼2%; Milone et al. 2012), which has been reduced through dynamical evolution (e.g., Ivanova et al. 2005).”
Formation and evolution of compact binaries in globular clusters – II. Binaries with neutron stars (2007, methodology): “In our first study of binary populations in GC cores (Ivanova et al. 2005a) we used a previous version ofStarTrack described in Belczynski et al. (2002).”
Compact Object Modeling with the StarTrack Population Synthesis Code (2005, methodology): “In that form it has been used for the study of binary fractions in globular clusters (Ivanova et al. 2005) and an investigation of intermediate-mass BHs in clusters and their connection to ultraluminous X-ray sources (Blecha et al. 2006).”
The stellar and sub-stellar IMF of simple and composite populations (2011, background): “However, again the story is by no means straightforward, because globular clusters have significantly smaller binary fractions than population II clusters (Ivanova et al. 2005).”
Binary Mergers and Growth of Black Holes in Dense Star Clusters (2005, methodology): “We follow the exact treatment of dynamical interactions of Ivanova et al. (2005) but include three-body binary formation with min ¼ 1 in a consistent manner (see, in particular, their x 3.4).”
THE DYNAMICAL EVOLUTION OF STELLAR BLACK HOLES IN GLOBULAR CLUSTERS (2014, background): “Our implementation follows Ivanova et al. (2005), Ivanova et al. (2010), and O’Leary et al. (2006), where the binary formation rate is expressed in terms of the binary hardness ratio (binary binding energy to background star kinetic energy) η = Gm1m2 rp 〈m〉σ2 .”
The ACS survey of Galactic globular clusters. XII. Photometric binaries along the main sequence (2011, methodology): “…clusters has been investigated in detail, mainly through MonteCarlo and Fokker-Plank simulations (e. g. Giersz & Spurzem 2000, Fregeau et al. 2003, Ivanova et al. 2005), N-body (e. g. Shara & Hurley 2002, Trenti, Heggie, & Hut 2007, Hurley, Aarseth, & Shara (2007), Fregeau et al. 2009, Marks,…”