Evolution of binary stars in multiple-population globular clusters

Journal
Date Issued
2015
Author(s)
Hong, Jongsuk
•
Vesperini, Enrico
•
•
McMillan, Stephen L. W.
•
D'Antona, Franca
•
D'Ercole, Annibale
DOI
Description
EV, JH and SLWM acknowledge support by grants NASA-NNX13AF45G and HST-12830.01-A. AS acknowledges the funding by the PRIN MIUR 2010-2011 ‘The Chemical and Dynamical Evolution of the Milky Way and Local Group Galaxies’ (PI: F. Matteucci). This research was supported in part by Lilly Endowment, Inc., through its support for the Indiana University Pervasive Technology Institute, and in part by the Indiana METACyt Initiative. The Indiana METACyt Initiative at IU is also supported in part by Lilly Endowment, Inc.
Abstract
The discovery of multiple stellar populations in globular clusters has implications for all the aspects of the study of these stellar systems. In this paper, by means of N-body simulations, we study the evolution of binary stars in multiple-population clusters and explore the implications of the initial differences in the spatial distribution of different stellar populations for the evolution and survival of their binary stars. Our simulations show that initial differences between the spatial distribution of first-generation (FG) and second-generation (SG) stars can leave a fingerprint in the current properties of the binary population. SG binaries are disrupted more efficiently than those of the FG population resulting in a global SG binary fraction smaller than that of the FG. As for surviving binaries, dynamical evolution produces a difference between the SG and the FG binary binding energy distribution with the SG population characterized by a larger fraction of high binding energy (more bound) binaries. We have also studied the dependence of the binary properties on the distance from the cluster centre. Although the global binary fraction decreases more rapidly for the SG population, the local binary fraction measured in the cluster inner regions may still be dominated by SG binaries. The extent of the differences between the surviving FG and SG binary binding energy distribution also varies radially within the cluster and is larger in the cluster inner regions.
Volume
449
Issue
1
Start page
629
Uri
Url
Issn Identifier
0035-8711
Ads BibCode
2015MNRAS.449..629H
Rights
open.access
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