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.

arXiv comment10 pages, 8 figures, 1 table; accepted for publication in MNRAS

References in corpus (16)

• Stellar population synthesis at the resolution of 2003
• Two distinct sequences of blue straggler stars in the globular cluster M30
• A Binary Origin for Blue Stragglers in Globular Clusters
• MOCCA code for star cluster simulations - I. Blue Stragglers, first results
• Evolution of Stellar Collision Products in Globular Clusters - II. Off-axis Collision
• A mass transfer origin for blue stragglers in NGC 188 as revealed by half-solar-mass companions
• Double Blue Straggler sequences in GCs: the case of NGC 362
• Where the Blue Stragglers Roam: Searching for a Link Between Formation and Environment
• A Panchromatic Study of the Globular Cluster NGC 1904. I: The Blue Straggler Population
• Evolution of the Binary Fraction in Dense Stellar Systems
• The Origins of Blue Stragglers and Binarity in Globular Clusters
• Chemical and kinematical properties of BSSs and HB stars in NGC 6397
• Consequences of Dynamical Disruption and Mass Segregation for the Binary Frequencies of Star Clusters
• Quantifying the Universality of the Stellar Initial Mass Function in Old Star Clusters
• Blue Straggler Star Populations in Globular Clusters: II. Proper-Motion Cleaned HST Catalogs of BSSs in 38 Galactic GCs
• An empirical tool to derive metallicity, reddening and distance for old stellar populations from near IR Color Magnitude Diagrams

Cited by in corpus (3)

• Discovery of a double Blue Straggler sequence in M15: new insight into the core-collapse process
• Determination of dynamical ages of open clusters through the A${}^{+}$ parameter -- I
• Discovery of double BSS sequences in the old Galactic open cluster Berkeley 17