期刊
ASTROPHYSICAL JOURNAL LETTERS
卷 719, 期 2, 页码 L213-L217出版社
IOP PUBLISHING LTD
DOI: 10.1088/2041-8205/719/2/L213
关键词
binaries: general; globular clusters: general; stars: abundances; stars: Population II
资金
- PRIN INAF
- DFG cluster of excellence
The determination of the Ba abundance in globular cluster ( GC) stars is a very powerful test to address several issues in the framework of multiple population scenarios. We measured the Ba content for a sample of more than 1200 stars in 15 Galactic GCs, using high-resolution FLAMES/Giraffe spectra. We found no variation in [ Ba/Fe] ratios for different stellar populations within each cluster; this means that low-mass asymptotic giant branch stars do not significantly contribute to the intracluster pollution. Very interestingly, we found that the fraction of Ba stars in first generation ( FG) stars is close to the values derived for field stars (similar to 2%); on the other hand, second generation ( SG) stars present a significantly lower fraction. An independent and successful test, based on radial velocity variations among giant stars in NGC 6121, confirms our finding: the binary fraction among FG stars is about similar to 12%, to be compared with similar to 1% of SG stars. This is an evidence that SG stars formed in a denser environment, where infant mortality of binary systems was particularly efficient.
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