EXTREME ENHANCEMENTS OF r-PROCESS ELEMENTS IN THE COOL METAL-POOR MAIN-SEQUENCE STAR SDSS J2357-0052

被引：45
作者：
Aoki, Wako [1 ,2 ]
Beers, Timothy C. [3 ,4 ]
Honda, Satoshi [5 ]
Carollo, Daniela [6 ,7 ,8 ]
机构：
[1] Natl Astron Observ, Tokyo 1818588, Japan
[2] Grad Univ Adv Studies, Dept Astron Sci, Tokyo 1818588, Japan
[3] Michigan State Univ, Dept Phys & Astron, E Lansing, MI 48824 USA
[4] Michigan State Univ, JINA, E Lansing, MI 48824 USA
[5] Kyoto Univ, Kwasan Observ, Yamashina Ku, Kyoto 607847, Japan
[6] Australian Natl Univ, Res Sch Astron & Astrophys, Weston, ACT 2611, Australia
[7] Mt Stromlo & Siding Spring Observ, Weston, ACT 2611, Australia
[8] INAF Osservatorio Astron Torino, I-10025 Pino Torinese, Italy
来源：
ASTROPHYSICAL JOURNAL LETTERS | 2010年 / 723卷 / 02期
基金：
美国国家科学基金会; 美国国家航空航天局;
关键词：
nuclear reactions; nucleosynthesis; abundances; stars: abundances; stars: Population II; HIGH-DISPERSION-SPECTROGRAPH; NEUTRON-CAPTURE ELEMENTS; DIGITAL SKY SURVEY; 1ST STARS; STELLAR HALO; BRANCH STARS; PROCESS-RICH; SURVEY HERES; CARBON-RICH; ABUNDANCES;
D O I：
10.1088/2041-8205/723/2/L201
中图分类号：
P1 [天文学];
学科分类号：
0704 ;
摘要：
We report the discovery of a cool metal-poor, main-sequence star exhibiting large excesses of r-process elements. This star is one of the two newly discovered cool subdwarfs (effective temperatures of 5000 K) with extremely low metallicity ([Fe/H] < -3) identified from follow-up high-resolution spectroscopy of metal-poor candidates from the Sloan Digital Sky Survey. SDSS J2357-0052 has [Fe/H]= -3.4 and [Eu/Fe]= +1.9, and exhibits a scaled solar r-process abundance pattern of heavy neutron-capture elements. This is the first example of an extremely metal-poor, main-sequence star showing large excesses of r-process elements; all previous examples of the large r-process-enhancement phenomena have been associated with metal-poor giants. The metallicity of this object is the lowest, and the excess of Eu ([Eu/Fe]) is the highest, among the r-process-enhanced stars found so far. We consider possible scenarios to account for the detection of such a star and discuss techniques to enable searches for similar stars in the future.
引用
收藏
页码：L201 / L206
页数：6
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