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

被引:92
作者
Aoki, W
Norris, JE
Ryan, SG
Beers, TC
Ando, H
机构
[1] Natl Astron Observ, Tokyo 1818588, Japan
[2] Australian Natl Univ, Res Sch Astron & Astrophys, Mt Stromlo Observ, Canberra, ACT 2611, Australia
[3] Open Univ, Dept Phys & Astron, Milton Keynes MK7 6AA, Bucks, England
[4] Michigan State Univ, Dept Phys & Astron, E Lansing, MI 48824 USA
基金
美国国家科学基金会;
关键词
nuclear reactions; nucleosynthesis; abundances stars : abundances; stars : carbon; stars : individual (CS 29498-043); stars : Population II;
D O I
10.1086/343761
中图分类号
P1 [天文学];
学科分类号
0704 ;
摘要
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] less than or equal to -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.
引用
收藏
页码:L141 / L144
页数:4
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