Blue straggler stars beyond the Milky Way: a non-segregated population in the Large Magellanic Cloud cluster NGC 2213

Abstract

Using the high-resolution observations obtained by the Hubble Space Telescope, we analyzed the blue straggler stars (BSSs) in the Large Magellanic Cloud cluster NGC 2213. We found that the radial distribution of BSSs is consistent with that of the normal giant stars in NGC 2213, showing no evidence of mass segregation. However, an analytic calculation carried out for these BSSs shows that they are already dynamically old, because the estimated half-mass relaxation time for these BSSs is significantly shorter than the isochronal age of the cluster. We also performed direct N-body simulations for a NGC 2213-like cluster to understand the dynamical processes that lead to this none-segregated radial distribution of BSSs. Our numerical simulation shows that the presence of black hole subsystems inside the cluster centre can significantly affect the dynamical evolution of BSSs. The combined effects of the delayed segregation, binary disruption and exchange interactions of BSS progenitor binaries may result in this none-segregated radial distribution of BSSs in NGC 2213.

11 pages, 9 figures, MNRAS accepted

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Cited by in corpus (4)

• Binary Black Hole Mergers from Globular Clusters: the Impact of Globular Cluster Properties
• Blue straggler stars beyond the Milky Way. II. A binary origin for blue straggler stars in Magellanic Cloud clusters
• Blue straggler stars beyond the Milky Way. III. Detection of evolved blue straggler candidates in Large Magellanic Cloud clusters
• Searching for chemical abundance variations in young star clusters in the Magellanic Clouds: NGC 411, NGC 1718 and NGC 2213