Chemical Composition of the Carbon-rich, Extremely Metal Poor Star CS 29498–043: A New Class of Extremely Metal Poor Stars with Excesses of Magnesium and Silicon
Chemical Composition of the Carbon-rich, Extremely Metal Poor Star CS 29498–043: A New Class of Extremely Metal Poor Stars with Excesses of Magnesium and Silicon
复制标题
DOI：
10.1086/343761
复制
发表时间：
2002-08
期刊：
影响因子：
--
通讯作者：
W. Aoki;J. Norris;S. Ryan;T. Beers;H. Ando
中科院分区：
文献类型：
--
作者：
W. Aoki;J. Norris;S. Ryan;T. Beers;H. Ando
我们分析了使用斯巴鲁望远镜高色散光谱仪获得的富含碳、极贫金属的星星CS 29498-043的高分辨率、高信噪比光谱。我们发现它的铁丰度极低（[Fe/H] = -3.7），使它成为少数已知的[Fe/H] ≤-3.5的恒星之一，而Mg和Si的丰度（[Mg/Fe] = +1.8和[Si/Fe] = +1.1）与没有碳过剩的类似金属丰度的恒星相比显着过剩。此外，还发现了N和Al的过度富集，这些特征与富碳、极贫金属的星星CS 22949-037相似。虽然样本很小，但我们对CS 29498-043的发现表明存在一类金属含量极低的恒星，它们含有大量的C、N、Mg和Si。
We analyze a high-resolution, high signal-to-noise ratio spectrum of the carbon-rich, extremely metal poor star CS 29498-043, obtained with the Subaru Telescope High Dispersion Spectrograph. We find its iron abundance is extremely low ([Fe/H] = -3.7), placing it among the few stars known with [Fe/H] ≤ -3.5, while Mg and Si are significantly overabundant ([Mg/Fe] = +1.8 and [Si/Fe] = +1.1) compared with stars of similar metallicity without carbon excess. Overabundances of N and Al were also found. These characteristics are similar to the carbon-rich, extremely metal poor star CS 22949-037. Although the sample is small, our discovery of CS 29498-043 suggests the existence of a class of extremely metal poor stars with large excesses of C, N, Mg, and Si.