期刊
ASTROPHYSICAL JOURNAL
卷 762, 期 1, 页码 -出版社
IOP PUBLISHING LTD
DOI: 10.1088/0004-637X/762/1/26
关键词
early universe; Galaxy: formation; Galaxy: halo; nuclear reactions, nucleosynthesis, abundances; stars: abundances
资金
- W. M. Keck Foundation
- Australian Research Council [DP03042613, DP0663562, DP0984924, FL110100012]
- Access to Major Research Facilities Program, under the International Science Linkages Program of the Australian Federal Government
- Major National Research Facilities program
- Global Networks program of Universitat Heidelberg
- The Milky Way System of the German Research Foundation (DFG) [Sonderforschungsbereich SFB 881]
- Physics Frontier Center/Joint Institute for Nuclear Astrophysics (JINA) [PHY 02-16783, PHY 08-22648]
- U.S. National Science Foundation
- Royal Swedish Academy of Sciences
- Swedish Research Council
- Knut and Alice Wallenberg Foundation
- European Southern Observatory's Director's Discretionary Time Program
- Keck Telescope under Gemini exchange time programs [GN-2007B-C-20, GN-2008A-C-6]
- STFC [ST/G002622/1] Funding Source: UKRI
- Science and Technology Facilities Council [ST/G002622/1] Funding Source: researchfish
We present a homogeneous chemical abundance analysis of 16 elements in 190 metal-poor Galactic halo stars (38 program and 152 literature objects). The sample includes 171 stars with [Fe/H] <= -2.5, of which 86 are extremely metal poor, [Fe/H] <= -3.0. Our program stars include 10 new objects with [Fe/H] <= -3.5. We identify a sample of normal metal-poor stars and measure the trends between [X/Fe] and [Fe/H], as well as the dispersion about the mean trend for this sample. Using this mean trend, we identify objects that are chemically peculiar relative to normal stars at the same metallicity. These chemically unusual stars include CEMP-no objects, one star with high [Si/Fe], another with high [Ba/Sr], and one with unusually low [X/Fe] for all elements heavier than Na. The Sr and Ba abundances indicate that there may be two nucleosynthetic processes at lowest metallicity that are distinct from the main r-process. Finally, for many elements, we find a significant trend between [X/Fe] versus T-eff, which likely reflects non-LTE and/or three-dimensional effects. Such trends demonstrate that care must be exercised when using abundance measurements in metal-poor stars to constrain chemical evolution and/or nucleosynthesis predictions.
作者
我是这篇论文的作者
点击您的名字以认领此论文并将其添加到您的个人资料中。
推荐
暂无数据