SPECTROSCOPIC ANALYSIS OF METAL-POOR STARS FROM LAMOST: EARLY RESULTS
文献类型：期刊论文
| 作者 | Li, Hai-Ning1 ; Zhao, Gang1; Christlieb, Norbert2; Wang, Liang1; Wang, Wei1; Zhang, Yong3; Hou, Yonghui3; Yuan, Hailong1
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| 刊名 | ASTROPHYSICAL JOURNAL
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| 出版日期 | 2015-01-10 |
| 卷号 | 798期号:2 |
| 关键词 | Galaxy: halo stars: abundances stars: Population II |
| 英文摘要 | We report on early results from a pilot program searching for metal-poor stars with LAMOST and follow-up high-resolution observation acquired with the MIKE spectrograph attached to the Magellan II telescope. We performed detailed abundance analysis for eight objects with iron abundances [Fe/H] < -2.0, including five extremely metal-poor (EMP; [Fe/H] < -3.0) stars with two having [Fe/H] < -3.5. Among these objects, three are newly discovered EMP stars, one of which is confirmed for the first time with high-resolution spectral observations. Three program stars are regarded as carbon-enhanced metal-poor (CEMP) stars, including two stars with no enhancement in their neutron-capture elements, which thus possibly belong to the class of CEMP-no stars; one of these objects also exhibits significant enhancement in nitrogen, and is thus a potential carbon and nitrogen-enhanced metal-poor star. The [X/Fe] ratios of the sample stars generally agree with those reported in the literature for other metal-poor stars in the same [Fe/H] range. We also compared the abundance patterns of individual program stars with the average abundance pattern of metal-poor stars and find only one chemically peculiar object with abundances of at least two elements (other than C and N) showing deviations larger than 0.5 dex. The distribution of [Sr/Ba] versus [Ba/H] agrees that an additional nucleosynthesis mechanism is needed aside from a single r-process. Two program stars with extremely low abundances of Sr and Ba support the prospect that both main and weak r-processes may have operated during the early phase of Galactic chemical evolution. The distribution of [C/N] shows that there are two groups of carbon-normal giants with different degrees of mixing. However, it is difficult to explain the observed behavior of the [C/N] of the nitrogen-enhanced unevolved stars based on current data. |
| 收录类别 | SCI |
| 语种 | 英语 |
| WOS记录号 | WOS:000350853700045 |
| 源URL | [http://ir.bao.ac.cn/handle/114a11/5731]  |
| 专题 | 国家天文台_光学天文研究部 |
| 作者单位 | 1.Chinese Acad Sci, Key Lab Opt Astron, Natl Astron Observ, Beijing 100012, Peoples R China 2.Heidelberg Univ, Zentrum Astron, D-69117 Heidelberg, Germany 3.Chinese Acad Sci, Nanjing Inst Astron Opt & Technol, Natl Astron Observ, Nanjing 210042, Jiangsu, Peoples R China |
| 推荐引用方式 GB/T 7714 | Li, Hai-Ning,Zhao, Gang,Christlieb, Norbert,et al. SPECTROSCOPIC ANALYSIS OF METAL-POOR STARS FROM LAMOST: EARLY RESULTS[J]. ASTROPHYSICAL JOURNAL,2015,798(2). |
| APA | Li, Hai-Ning.,Zhao, Gang.,Christlieb, Norbert.,Wang, Liang.,Wang, Wei.,...&Yuan, Hailong.(2015).SPECTROSCOPIC ANALYSIS OF METAL-POOR STARS FROM LAMOST: EARLY RESULTS.ASTROPHYSICAL JOURNAL,798(2). |
| MLA | Li, Hai-Ning,et al."SPECTROSCOPIC ANALYSIS OF METAL-POOR STARS FROM LAMOST: EARLY RESULTS".ASTROPHYSICAL JOURNAL 798.2(2015). |
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来源：国家天文台
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