Building blocks of the Milky Way halo

C. Chung, Y. W. Lee, M. Pasquato

    Research output: Contribution to journalConference articlepeer-review


    Recently, Deason et al. suggested that the number ratio between blue stragglers (BSs) and blue horizontal branch stars (BHBs) can be used as a population indicator of various stellar systems. Using this number ratio, they suggested that the Milky Way outer halo formed mostly from dwarf spheroidals rather than globular clusters (GCs). However, we demonstrate that this result is biased because they neglect the effect of BHB stars from helium-enhanced second-generation population on the number ratio. We also perform dynamical evolution models and found that the high BS-to-BHB ratio observed in the outer halo fields is most likely due to the preferential removal of the first-generation stars in GCs. Therefore, the BS-to-BHB number ratio is not a good population indicator for claiming that more massive dwarf galaxies are the main building blocks of the Milky Way outer halo.

    Original languageEnglish (US)
    Pages (from-to)681-682
    Number of pages2
    JournalMemorie della Societa Astronomica Italiana - Journal of the Italian Astronomical Society
    Issue number4
    StatePublished - 2016
    Event2016 Cosmic-Lab Conference: Star Clusters as Cosmic Laboratories for Astrophysics, Dynamics and Fundamental Physics, MODEST 2016 - Bologna, Italy
    Duration: Apr 18 2016Apr 22 2016


    • Galaxy: halo
    • Globular clusters: general
    • Stars: abundances
    • Stars: evolution
    • Stars: horizontal branch

    ASJC Scopus subject areas

    • Electrical and Electronic Engineering
    • Radiology Nuclear Medicine and imaging
    • Astronomy and Astrophysics
    • Instrumentation
    • Atomic and Molecular Physics, and Optics


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