Oxygen Overabundance in the Extremely Iron-poor Star CS 29498-043
Oxygen Overabundance in the Extremely Iron-poor Star CS 29498-043
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DOI：
10.1086/420686
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发表时间：
2004-02
期刊：
影响因子：
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通讯作者：
W. Aoki;J. Norris;S. Ryan;T. Beers;N. Christlieb;S. Tsangarides;H. Ando
中科院分区：
文献类型：
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作者：
W. Aoki;J. Norris;S. Ryan;T. Beers;N. Christlieb;S. Tsangarides;H. Ando
利用Subaru望远镜新的高分辨率、高信噪比光谱，获得了碳增强、极贫铁（[Fe/H]-3.5）的星星CS 29498-043的丰度分析。在6300 nm处的[O I]禁戒线和7771-7776 nm处的O I三重态特征都被清晰地探测到。氧的过剩是显著的（[O/Fe] > 2）。此外，Na、Co和Ni的丰度也是新测量的。该天体从C到Ni的丰度模式与CS 22949-037非常相似，CS 22949-037是另一颗极度贫金属的星星，含有大量的C、N、O和α元素。这两颗恒星的丰度模式表明，在银河系核合成的早期，超新星的祖先从它们的铁核中喷出的物质相对较少。当把C、N和O元素包括在总金属量中时，这些天体的金属丰度并不像大多数贫金属恒星那样低，这表明这些缺铁天体的形成过程与其他大部分缺金属恒星的形成过程完全不同。
An abundance analysis for the carbon-enhanced, extremely iron-poor ([Fe/H] ~ -3.5) star CS 29498-043 has been obtained using new high-resolution, high signal-to-noise ratio spectra from the Subaru Telescope. The [O I] forbidden line at 6300 Å and the O I triplet feature at 7771-7776 Å are both clearly detected. The overabundance of oxygen is significant ([O/Fe] > 2). In addition, Na, Co, and Ni abundances have been newly measured. The abundance pattern from C to Ni of this object is quite similar to that of CS 22949-037, another extremely metal-poor star with large excesses of C, N, O, and the α-elements. The abundance patterns of these two stars suggest the existence of supernovae progenitors that ejected relatively little material from their iron cores during the very early era of nucleosynthesis in the Galaxy. The metallicity in these objects, when one includes the elements C, N, and O in the tally of total metals, is not as low as in the most metal-poor stars, suggesting the existence of quite different formation processes for these iron-deficient objects than pertain to the bulk of other metal-deficient stars.