Blue straggler stars beyond the Milky Way. II. A binary origin for blue straggler stars in Magellanic Cloud clusters

Weijia Sun, Chengyuan Li, Richard de Grijs, Licai Deng

Research output: Contribution to journalArticle

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Abstract

We have analyzed populations of blue straggler stars (BSSs) in 24 Magellanic Cloud (MC) star clusters using multi-passband Hubble Space Telescope images. We compiled a homogeneous BSS database, containing both traditional and evolved BSSs. We uncovered a sublinear correlation between the number of BSSs in the cluster cores and the clusters' core masses, characterized by a power-law index of 0.51 0.07. For low stellar collision rates, the mass-normalized number of BSSs depends only weakly (or perhaps not at all) on the collision rate, implying that the binary-driven BSS formation channel dominates. Comparison with simulations suggests that stellar collisions contribute less than 20% to the total number of BSSs formed. Further tests, including the analysis of the BSS-specific frequencies and their population numbers at larger cluster radii, suggest that binary interactions may be their main formation channel, hinting at an anti-correlation between a cluster's binary fraction and its core mass.

Original languageEnglish
Article number133
Pages (from-to)1-11
Number of pages11
JournalAstrophysical Journal
Volume862
Issue number2
DOIs
Publication statusPublished - 1 Aug 2018

Bibliographical note

Copyright 2018 The American Astronomical Society. First published in the Astrophysical journal, 862(2), 133, 2018, published by IOP Publishing. The original publication is available at http://www.doi.org/10.3847/1538-4357/aacc6b. Version archived for private and non-commercial use with the permission of the author/s and according to publisher conditions. For further rights please contact the publisher.

Keywords

  • blue stragglers
  • galaxies: star clusters: general
  • Magellanic Clouds

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