LITHIUM ABUNDANCES OF EXTREMELY METAL-POOR TURNOFF STARS
LITHIUM ABUNDANCES OF EXTREMELY METAL-POOR TURNOFF STARS
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DOI：
10.1088/0004-637x/698/2/1803
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发表时间：
2008-05
期刊：
影响因子：
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通讯作者：
W. Aoki;P. Barklem;T. Beers;N. Christlieb;S. Inoue;A. G. Pérez;J. Norris;D. Carollo
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文献类型：
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作者：
W. Aoki;P. Barklem;T. Beers;N. Christlieb;S. Inoue;A. G. Pérez;J. Norris;D. Carollo
根据斯巴鲁望远镜高色散谱仪获得的高分辨光谱的长余辉分析，我们测定了11颗贫金属关闭星的Li丰度，其中8颗具有[Fe/H]<；−3。这项研究首次确定了这八颗恒星中的四颗的锂丰度。有效温度由H-α和H-β的剖面分析确定。虽然有7颗恒星的Li丰度与乌托普兰值一样高，但其余4颗具有[Fe/H]和lt；−3的天体具有A(Li)=LOG(Li/H)+12≲2.0，这证实了存在Li丰度较低的极贫金属(EMP)关闭星。具有[Fe/H]和lt；−3的恒星的Li丰度平均值比金属丰度较高的恒星低0.2dex。我们对具有[Fe/H]和lt；−3的恒星的测量没有得到对Li丰度与金属丰度的依赖或散射的明确限制。我们研究了Li丰度与有效温度、与Na、Mg、Sr丰度以及与运动学性质的关联，但在EMP星样品中没有看到明显的关联。
We have determined Li abundances for eleven metal-poor turnoff stars, among which eight have [Fe/H] <−3, based on LTE analyses of high-resolution spectra obtained with the High Dispersion Spectrograph on the Subaru Telescope. The Li abundances for four of these eight stars are determined for the first time by this study. Effective temperatures are determined by a profile analysis of Hα and Hβ. While seven stars have Li abundances as high as the Spite Plateau value, the remaining four objects with [Fe/H] <−3 have A(Li) =log (Li/H)+ 12 ≲ 2.0, confirming the existence of extremely metal-poor (EMP) turnoff stars having low Li abundances, as reported by previous work. The average of the Li abundances for stars with [Fe/H]<−3 is lower by 0.2 dex than that of the stars with higher metallicity. No clear constraint on the metallicity dependence or scatter of the Li abundances is derived from our measurements for the stars with [Fe/H]<−3. Correlations of the Li abundance with effective temperatures, with abundances of Na, Mg, and Sr, and with the kinematical properties are investigated, but no clear correlation is seen in the EMP star sample.