Blue Straggler Stars Beyond the Milky Way. III. Detection of Evolved Blue Straggler Candidates in Large Magellanic Cloud Clusters

We analyze Hubble Space Telescope observations of nine Large Magellanic Cloud star clusters with ages of 1-2 Gyr to search for evolved counterparts of blue straggler stars. Near the red clump regions in the clusters' color-magnitude diagrams, we find branches of evolved stars that are much brig...

Full description

Saved in:
Bibliographic Details
Published in:The Astronomical journal 2018-09, Vol.156 (3), p.110
Main Authors: Li, Chengyuan, Deng, Licai, Bekki, Kenji, Hong, Jongsuk, Grijs, Richard de, For, Bi-Qing
Format: Article
Language:English
Subjects:
Astronomical models
Astronomy
blue stragglers
Cloud clusters
Cluster analysis
Computer simulation
galaxies: star clusters
Hertzsprung-Russell and C-M diagrams
Hubble Space Telescope
Magellanic Clouds
Milky Way
Organic chemistry
Photometry
Space telescopes
Spatial distribution
Star clusters
Statistical tests
Stellar age
Stellar evolution
Stellar models
Citations: Items that this one cites
Items that cite this one
Online Access:Get full text
Tags: Add Tag
No Tags, Be the first to tag this record!
Description
Summary:We analyze Hubble Space Telescope observations of nine Large Magellanic Cloud star clusters with ages of 1-2 Gyr to search for evolved counterparts of blue straggler stars. Near the red clump regions in the clusters' color-magnitude diagrams, we find branches of evolved stars that are much brighter than normal evolved stars. We examine the effects of photometric artifacts, differential reddening, and field contamination. We conclude that these bright evolved stars cannot be explained by any of these effects. Our statistical tests show that the contributions of photometric uncertainties, crowding effects, and differential reddening to these bright evolved stars are insufficient to fully explain their presence. Based on isochrone fitting, we have also ruled out the possibility that these bright evolved stars could be reproduced by an internal chemical abundance spread. The spatial distributions of the bright evolved stars exhibit clear concentrations that cannot be explained by homogeneously distributed field stars. This is further confirmed based on Monte Carlo-based tests. By comparing our observations with stellar evolution models, we find that the masses of most of the bright evolved stars do not exceed twice the average mass of normal evolved stars. We suggest that these bright evolved stars are, in fact, evolved blue straggler stars.
ISSN:0004-6256
1538-3881
DOI:10.3847/1538-3881/aad463