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arXiv · astro-ph/9904152

An Extremely Lithium-Rich Bright Red Giant in the Globular Cluster M3

Robert P. Kraft·Ruth C. Peterson·Puragra Guhathakurta·Christopher Sneden·Jon P. Fulbright·G. Edward Langer
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Abstract

We have serendipitously discovered an extremely lithium-rich star on the red giant branch of the globular cluster M3 (NGC 5272). An echelle spectrum obtained with the Keck I HIRES reveals a Li I 6707 Angstrom resonance doublet of 520 milli-Angstrom equivalent width, and our analysis places the star among the most Li-rich giants known: log[epsilon(Li)] ~= +3.0. We determine the elemental abundances of this star, IV-101, and three other cluster members of similar luminosity and color, and conclude that IV-101 has abundance ratios typical of giants in M3 and M13 that have undergone significant mixing. We discuss mechanisms by which a low-mass star may be so enriched in Li, focusing on the mixing of material processed by the hydrogen-burning shell just below the convective envelope. While such enrichment could conceivably only happen rarely, it may in fact regularly occur during giant-branch evolution but be rarely detected because of rapid subsequent Li depletion.

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Robert P. Kraft, Ruth C. Peterson, Puragra Guhathakurta, Christopher Sneden, Jon P. Fulbright, G. Edward Langer. 1999-04-12. An Extremely Lithium-Rich Bright Red Giant in the Globular Cluster M3. https://doi.org/10.1086/312061

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