How Stellar Encounter Shape the Binary Populations of Open Clusters

Type Conference Paper
Names Aaron M. Geller, R. D. Mathieu, J. R. Hurley
Conference Name American Astronomical Society Meeting Abstracts, #221, #331.04
Volume 221
Date January 1, 2013
Library Catalog NASA ADS
Abstract Dynamical encounters involving binary stars influence the dynamical evolution of star clusters. Exotic stars, including some blue stragglers and X-ray sources, are observable products of the more “violent” dynamical encounters that can result in the significant hardening of binary orbits and even direct stellar collisions. Yet the majority of stellar encounters, and particularly those in open clusters, are less energetic and do not result in such dramatic changes to the binaries. Indeed our sophisticated N-body model of the old (7 Gyr) open cluster NGC 188 predicts that, apart from stellar exotica, the signatures of past dynamical encounters may only be detectable by examining the orbital parameters, and particularly the eccentricities, of the binaries with periods much longer than 1000 days. Furthermore, our N-body model predicts that the distributions of orbital parameters of the short-period (roughly P<1000 days) solar-type binaries will remain roughly constant, even after many Gyr of evolution within a rich open cluster. This suggests that observations of the present-day binaries in even old open clusters may still provide valuable information about their primordial binary populations.
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