论文标题
富人缺乏亲密的邻居：蓝色巨质分数对金属性的依赖性
The Rich Lack Close Neighbours: The Dependence of Blue-Straggler Fraction on Metallicity
论文作者
论文摘要
在我们自己的银河系和卫星星系中，已经在星团和田间种群中鉴定出蓝色Straggler星（BSS）。它们表现为恒星比主要的旧人口更蓝，并且更发光，并且通常具有遵循旧人口的空间分布。他们的祖细胞可能是近亲。我们研究了矮球星系（DSPH）中BSS种群的趋势，并在银河系的凸起中研究，并在BSS的相对频率与父母的金属性之间找到抗相关性。金属贫困矮星系中BSS的发生率约为太阳金属凸出种群的两倍。随着金属性镜的增加，BSS相对种群减少的趋势是在银河系的田间人口中发现的近二元分数。我们认为，在低密度环境中BSS形成的主要模式可能是近二元系统中的传质。然后得出结论，在我们的银河系中，BSS的BSS趋势之间的相似性支持以下提议：尽管环境中的多样性，Proto-Stellar Discs的强力不稳定性，但恒星形成过程中的小规模碎片是由相同的主要物理过程驱动的。
Blue straggler stars (BSS) have been identified in star clusters and in field populations in our own Milky Way galaxy and in its satellite galaxies. They manifest as stars bluer and more luminous than the dominant old population, and usually have a spatial distribution that follows the old population. Their progenitors are likely to have been close binaries. We investigate trends of the BSS population in dwarf spheroidal galaxies (dSph) and in the bulge of the Milky Way and find an anti-correlation between the relative frequency of BSS and the metallicity of the parent population. The rate of occurrence of BSS in the metal-poor dwarf galaxies is approximately twice that found in the solar-metallicity bulge population. This trend of decreasing relative population of BSS with increasing metallicity mirrors that found for the close-binary fraction in the field population of the Milky Way. We argue that the dominant mode of BSS formation in low-density environments is likely to be mass transfer in close-binary systems. It then follows that the similarity between the trends for BSS in the dSph and field stars in our Galaxy supports the proposal that the small-scale fragmentation during star formation is driven by the same dominant physical process, despite the diversity in environments, plausibly gravitational instability of proto-stellar discs.
