A LITHIUM-RICH RED GIANT BELOW THE CLUMP IN THE KEPLER CLUSTER, NGC 6819

被引：37

作者：

Anthony-Twarog, Barbara J. ^{[1
]}

Deliyannis, Constantine P. ^{[2
]}

Rich, Evan ^{[1
]}

Twarog, Bruce A. ^{[1
]}

机构：

[1] Univ Kansas, Dept Phys & Astron, Lawrence, KS 66045 USA

[2] Indiana Univ, Dept Astron, Bloomington, IN 47405 USA

来源：

ASTROPHYSICAL JOURNAL LETTERS | 2013年 / 767卷 / 01期

基金：

美国国家科学基金会;

关键词：

open clusters and associations: individual (NGC 6819); stars: abundances; stars: chemically peculiar; ABUNDANCES; STARS; PHOTOMETRY; SPECTROSCOPY; MEMBERSHIP; DEPLETION; SPECTRA;

D O I：

10.1088/2041-8205/767/1/L19

中图分类号：

P1 [天文学];

学科分类号：

0704 ;

摘要：

WIYN/HYDRA spectra in the Li 6708 angstrom region have been obtained for 332 probable members of the old open cluster, NGC 6819. Preliminary analysis shows a pattern of Li depletion from the top of the turnoff to the base of the giant branch. Starting 1 mag below the level of the clump, all brighter giants have A(Li) below 1.0, with most having upper limits below 0.5. Star W007017, located below the first-ascent red giant bump is Li-rich with A(Li) = 2.3. As a highly probable single-star astrometric and radial-velocity cluster member, its discrepant asteroseismic membership could be a by-product of the processes that triggered Li enhancement. Its color-magnitude diagram location is consistent with only one proposed enhanced mixing process among first-ascent red giants.

引用

页数：4

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