Constraints on blue straggler formation mechanisms in Galactic globular clusters from proper motion velocity distributions
Abstract
For a sample of 38 Galactic globular clusters (GCs), we confront the observed distributions of blue straggler (BS) proper motions and masses (derived from isochrone fitting) from the BS catalog of Simunovic & Puzia with theoretical predictions for each of the two main competing BS formation mechanisms. These are mass transfer from an evolved donor on to a main-sequence (MS) star in a close binary system, and direct collisions involving MS stars during binary encounters. We use the \texttt{FEWBODY} code to perform simulations of single-binary and binary-binary interactions. This provides collisional velocity and mass distributions for comparison to the observed distributions. Most clusters are consistent with BSs derived from a dynamically relaxed population, supportive of the binary mass-transfer scenario. In a few clusters, including all the post-core collapse clusters in our sample, the collisional velocities provide the best fit.
Keywords
Cite
@article{arxiv.1810.01895,
title = {Constraints on blue straggler formation mechanisms in Galactic globular clusters from proper motion velocity distributions},
author = {N. W. C. Leigh and T. Panurach and M. Simunovic and A. M. Geller and D. Zurek and M. M. Shara and A. Sills and C. Knigge and N. M. Gosnell and R. Mathieu and T. H. Puzia and J. Ventura and Q. Minor},
journal= {arXiv preprint arXiv:1810.01895},
year = {2018}
}
Comments
10 pages, 8 figures, 1 table; accepted for publication in MNRAS