OBSERVATIONAL CONSTRAINTS ON FIRST-STAR NUCLEOSYNTHESIS. II. SPECTROSCOPY OF AN ULTRA METAL-POOR CEMP-no STAR
OBSERVATIONAL CONSTRAINTS ON FIRST-STAR NUCLEOSYNTHESIS. II. SPECTROSCOPY OF AN ULTRA METAL-POOR CEMP-no STAR
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DOI：
10.3847/0004-637x/833/1/21
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发表时间：
2016-09
期刊：
影响因子：
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通讯作者：
V. Placco;A. Frebel;T. Beers;Jinmi Yoon;A. Chiti;A. Heger;Conrad Chan;A. Casey;N. Christlieb
中科院分区：
文献类型：
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作者：
V. Placco;A. Frebel;T. Beers;Jinmi Yoon;A. Chiti;A. Heger;Conrad Chan;A. Casey;N. Christlieb
我们报告了HE 0020-1741的第一个高分辨率光谱分析，这是一颗从汉堡/ESO调查中选择的明亮（V = 12.9），超金属贫（=−4.1），碳增强（= +1.7）的恒星。这颗恒星显示出低丰度的中子捕获元素（=−1.1）和绝对碳丰度A(C) = 6.1；无论基于哪一种标准，HE 0020-1741都被归类为碳增强的贫金属恒星，没有增强的中子捕获元素（cepp -no）。我们发现HE 0020-1741的轻元素丰度模式与预测的大质量（M =），原始组成，超新星（SN）祖先的产量一致。我们还将文献中其他超贫金属恒星的丰度模式与可用的C、N、Na、Mg和Fe丰度测量方法进行了比较，并采用了广泛的SN模型网格（覆盖质量范围），以探索它们可能的恒星祖先的性质。我们的结果表明，至少需要两类祖星，因为在这项工作中研究的一半以上的样本（12颗恒星中的7颗）的丰度模式不能通过预测的产量轻易地再现。
We report on the first high-resolution spectroscopic analysis of HE 0020–1741, a bright (V = 12.9), ultra metal-poor ( = −4.1), carbon-enhanced ( = +1.7) star selected from the Hamburg/ESO Survey. This star exhibits low abundances of neutron-capture elements ( = −1.1) and an absolute carbon abundance A(C) = 6.1; based on either criterion, HE 0020–1741 is subclassified as a carbon-enhanced metal-poor star without enhancements in neutron-capture elements (CEMP-no). We show that the light-element abundance pattern of HE 0020–1741 is consistent with predicted yields from a massive (M = ), primordial-composition, supernova (SN) progenitor. We also compare the abundance patterns of other ultra metal-poor stars from the literature with available measures of C, N, Na, Mg, and Fe abundances with an extensive grid of SN models (covering the mass range ), in order to probe the nature of their likely stellar progenitors. Our results suggest that at least two classes of progenitors are required at , as the abundance patterns for more than half of the sample studied in this work (7 out of 12 stars) cannot be easily reproduced by the predicted yields.