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首页> 外文期刊>The Astrophysical journal >THE BEST AND BRIGHTEST METAL-POOR STARS*
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THE BEST AND BRIGHTEST METAL-POOR STARS*

机译:最佳和最亮的贫金属星级*

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The chemical abundances of large samples of extremely metal-poor (EMP) stars can be used to investigate metal-free stellar populations, supernovae, and nucleosynthesis as well as the formation and galactic chemical evolution of the Milky Way and its progenitor halos. However, current progress on the study of EMP stars is being limited by their faint apparent magnitudes. The acquisition of high signal-to-noise spectra for faint EMP stars requires a major telescope time commitment, making the construction of large samples of EMP star abundances prohibitively expensive. We have developed a new, efficient selection that uses only public, all-sky APASS optical, 2MASS near-infrared, and WISE mid-infrared photometry to identify bright metal-poor star candidates through their lack of molecular absorption near 4.6 microns. We have used our selection to identify 11,916 metal-poor star candidates with V 14, increasing the number of publicly available candidates by more than a factor of five in this magnitude range. Their bright apparent magnitudes have greatly eased high-resolution follow-up observations that have identified seven previously unknown stars with [Fe/H] –3.0. Our follow-up campaign has revealed that % of our candidates have [Fe/H] –3.0 and % have –3.0 [Fe/H] –2.0. The bulge is the most likely location of any existing Galactic Population III stars, and an infrared-only variant of our selection is well suited to the identification of metal-poor stars in the bulge. Indeed, two of our confirmed metal-poor stars with [Fe/H] –2.7 are within about 2 kpc of the Galactic center. They are among the most metal-poor stars known in the bulge.
机译:大量极贫金属(EMP)星的化学丰度可用于研究无金属的恒星种群,超新星和核合成,以及银河系及其祖先晕的形成和银河系化学演化。但是,目前在EMP恒星研究方面的进展受到其微弱的视星等限制。要获得微弱的EMP恒星的高信噪比光谱,需要花费大量的望远镜时间,这使得EMP恒星丰度大样本的构建极其昂贵。我们已经开发出一种新的高效选择,该选择仅使用公共的全天空APASS光学,2MASS近红外和WISE中红外光度法通过在4.6微米附近缺乏分子吸收来识别亮金属贫乏的恒星候选物。我们已使用我们的选择来确定V小于14的11,916个金属贫乏的星标候选人,在这个数量级范围内,可公开获得的候选人数量增加了五倍以上。它们明亮的视星等极大地缓解了高分辨率的后续观测,该观测已识别出[Fe / H] –3.0的七个先前未知的恒星。我们的后续活动表明,我们的候选人中有[Fe / H] -3.0为%,有-3.0 [Fe / H] -2.0为%。凸起是所有现有银河III号恒星中最有可能的位置,我们选择的仅红外变体非常适合识别凸起中金属贫乏的恒星。确实,我们确认的[Fe / H] –2.7的金属贫乏恒星中有两颗位于银河系中心约2 kpc之内。它们是凸出部中最贫金属的恒星之一。

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