An Unexpected Detection of Bifurcated Blue Straggler Sequences in the Young Globular Cluster NGC 2173∗ ∗ C. Li, L. Deng, and R. de Grijs jointly designed this project

The bifurcated patterns in the color-magnitude diagrams of blue straggler stars (BSSs) have attracted significant attention. This type of special (but rare) pattern of two distinct blue straggler sequences is commonly interpreted as evidence that cluster core-collapse-driven stellar collisions are a...

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Published inThe Astrophysical journal Vol. 856; no. 1
Main Authors Li, Chengyuan, Deng, Licai, Grijs, Richard de, Jiang, Dengkai, Xin, Yu
Format Journal Article
LanguageEnglish
Published The American Astronomical Society 21.03.2018
Subjects
blue stragglers
galaxies: star clusters: individual (NGC 2173)
Hertzsprung-Russell and C-M diagrams
Magellanic Clouds
stars: kinematics and dynamics
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Summary:The bifurcated patterns in the color-magnitude diagrams of blue straggler stars (BSSs) have attracted significant attention. This type of special (but rare) pattern of two distinct blue straggler sequences is commonly interpreted as evidence that cluster core-collapse-driven stellar collisions are an efficient formation mechanism. Here, we report the detection of a bifurcated blue straggler distribution in a young Large Magellanic Cloud cluster, NGC 2173. Because of the cluster's low central stellar number density and its young age, dynamical analysis shows that stellar collisions alone cannot explain the observed BSSs. Therefore, binary evolution is instead the most viable explanation of the origin of these BSSs. However, the reason why binary evolution would render the color-magnitude distribution of BSSs bifurcated remains unclear.
Bibliography:Stars and Stellar Physics
AAS08228
ISSN:0004-637X
1538-4357
DOI:10.3847/1538-4357/aaad65