TY - JOUR

T1 - INTERRUPTED BINARY MASS TRANSFER IN STAR CLUSTERS

AU - Leigh, Nathan W.C.

AU - Geller, Aaron M.

AU - Toonen, Silvia

N1 - Funding Information:
The authors would like to thank an anonymous reviewer for useful suggestions for improvement. N.W.C.L. is grateful for the generous support of an NSERC Postdoctoral Fellowship. A.M.G. is funded by a National Science Foundation Astronomy and Astrophysics Postdoctoral Fellowship under Award No. AST-1302765.
Publisher Copyright:
© 2016. The American Astronomical Society. All rights reserved..

PY - 2016/2/10

Y1 - 2016/2/10

N2 - Binary mass transfer (MT) is at the forefront of some of the most exciting puzzles of modern astrophysics, including SNe Ia, gamma-ray bursts, and the formation of most observed exotic stellar populations. Typically, the evolution is assumed to proceed in isolation, even in dense stellar environments such as star clusters. In this paper, we test the validity of this assumption via the analysis of a large grid of binary evolution models simulated with the SeBa code. For every binary, we calculate analytically the mean time until another single or binary star comes within the mean separation of the mass-transferring binary, and compare this timescale to the mean time for stable MT to occur. We then derive the probability for each respective binary to experience a direct dynamical interruption. The resulting probability distribution can be integrated to give an estimate for the fraction of binaries undergoing MT that are expected to be disrupted as a function of the host cluster properties. We find that for lower-mass clusters (≲104 M⊙), on the order of a few to a few tens of percent of binaries undergoing MT are expected to be interrupted by an interloping single, or more often binary, star, over the course of the cluster lifetime, whereas in more massive globular clusters we expect 蠐1% to be interrupted. Furthermore, using numerical scattering experiments performed with the FEWBODY code, we show that the probability of interruption increases if perturbative fly-bys are considered as well, by a factor ∼2.

AB - Binary mass transfer (MT) is at the forefront of some of the most exciting puzzles of modern astrophysics, including SNe Ia, gamma-ray bursts, and the formation of most observed exotic stellar populations. Typically, the evolution is assumed to proceed in isolation, even in dense stellar environments such as star clusters. In this paper, we test the validity of this assumption via the analysis of a large grid of binary evolution models simulated with the SeBa code. For every binary, we calculate analytically the mean time until another single or binary star comes within the mean separation of the mass-transferring binary, and compare this timescale to the mean time for stable MT to occur. We then derive the probability for each respective binary to experience a direct dynamical interruption. The resulting probability distribution can be integrated to give an estimate for the fraction of binaries undergoing MT that are expected to be disrupted as a function of the host cluster properties. We find that for lower-mass clusters (≲104 M⊙), on the order of a few to a few tens of percent of binaries undergoing MT are expected to be interrupted by an interloping single, or more often binary, star, over the course of the cluster lifetime, whereas in more massive globular clusters we expect 蠐1% to be interrupted. Furthermore, using numerical scattering experiments performed with the FEWBODY code, we show that the probability of interruption increases if perturbative fly-bys are considered as well, by a factor ∼2.

KW - binaries: close

KW - binaries: general

KW - galaxies: star clusters: general

KW - globular clusters: general

KW - open clusters and associations: general

KW - stars: kinematics and dynamics

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U2 - 10.3847/0004-637X/818/1/21

DO - 10.3847/0004-637X/818/1/21

M3 - Article

AN - SCOPUS:84959167339

SN - 0004-637X

VL - 818

JO - Astrophysical Journal

JF - Astrophysical Journal

IS - 1

M1 - 21

ER -