![]() ![]() The results indicate the existence of an efficient process to enrich Li in a small fraction of low-mass stars at the main-sequence or subgiant phase. The sample is distributed over a wide range of evolutionary stages, including five unevolved stars, showing no clear abundance anomaly in other elements. We report on the discovery of 12 very metal-poor stars that have large excesses of Li, including an object having more than 100 times higher Li abundance than the values found in usual objects, which is the largest excess in metal-poor stars known to date. However, a small number of stars have exceptionally high Li abundances, for which no convincing models have been established. Li abundances in the bulk of low-mass metal-poor stars are well reproduced by stellar evolution models adopting a constant initial abundance. Li, Haining Aoki, Wako Matsuno, Tadafumi Bharat Kumar, Yerra Shi, Jianrong Suda, Takuma Zhao, Gang The CNO values also vary widely from the values found in the solar system.Įnormous Li Enhancement Preceding Red Giant Phases in Low-mass Stars in the Milky Way Halo The O-12/O-18 ratios of red giants are distinctly different from those in interstellar molecular clouds. The contribution of intermediate-mass stars to galactic nuclear evolution is discussed after comparing red giant abundances with ISM abundances, particularly the isotopes O-16, -17 and -18. ![]() The data included isotope abundance measurements for the atmospheres and recent ejecta of cool giants, e.g., carbon stars, S-type stars, red supergiants and oxygen-rich giants beginning an ascent of the giant branch. ![]() ![]() Observational data on CNO abundance ratios in red giants and the interstellar medium (ISM) are analyzed for the implications for the production and distribution of CNO nuclides. ![]()
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