论文标题
在非常金属可怜的恒星样品中的详细丰度
Detailed abundances in a sample of very metal poor stars
论文作者
论文摘要
未进化的金属可怜的恒星是星系早期演变的见证。确定其详细的化学成分是了解我们银河系的化学历史的重要工具。对其化学成分的研究也可以用来限制富含星际培养基的第一代超新星的核合成。目的是观察从SDSS DR12释放中选择的极贫困恒星（EMP恒星）的样品，并确定其化学成分。 我们使用Subaru望远镜上的HDS获得了五颗星样品的高分辨率光谱，并使用标准的1D模型来计算丰度。我们分析的恒星在-3.50 dex和-4.25 dex之间具有金属度[Fe/H]。 我们确认从低分辨率光谱中选择的五个金属差候选者非常贫穷。 我们提出，发现了新的超金属贫困星（UMP Star），其金属性为[Fe/H] = -4.25 Dex（SDSS〜J1050032.34 $ - $ 241009.7）。我们在这条星星中测量了锂的上限（log（li/h）<= 2.0。我们发现，样品中的4个最贫穷的恒星比锂锂的锂含量低。我们在恒星样品中获得了碳的上限。它们都不属于高碳和恒星。我们测量了MG和Ca的恒星。
Unevolved metal poor stars are the witness of the early evolution of the Galaxy. The determination of their detailed chemical composition is an important tool to understand the chemical history of our Galaxy. The study of their chemical composition can also be used to constrain the nucleosynthesis of the first generation of supernovae that enriched the interstellar medium. The aim is to observe a sample of extremely metal poor stars (EMP stars) candidates selected from SDSS DR12 release and determine their chemical composition. We obtained high resolution spectra of a sample of five stars using HDS on Subaru telescope and used standard 1D models to compute the abundances. The stars we analysed have a metallicity [Fe/H] between -3.50 dex and -4.25 dex . We confirm that the five metal poor candidates selected from low resolution spectra are very metal poor. We present, the discovery of a new ultra metal-poor star (UMP star) with a metallicity of [Fe/H]= -4.25 dex (SDSS~J1050032.34$-$241009.7). We measured in this star an upper limit of lithium ( log(Li/H) <= 2.0. We found that the 4 most metal poor stars of our sample have a lower lithium abundance than the Spite plateau lithium value. We obtain upper limits for carbon in the sample of stars. None of them belong to the high carbon band. We measured abundances of Mg and Ca in most of the stars and found three new alpha-poor stars.
