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arXiv · 2403.01815

Lithium Abundances from the LAMOST Med-Resolution Survey Data Release 9

Ming-Yi Ding·Jian-Rong Shi·Hong-liang Yan·Chun-Qian Li·Qi Gao·Tian-Yi Chen·Jing-Hua Zhang·Shuai Liu·Xiao-Jin Xie·Yao-Jia Tang·Ze-Ming Zhou·Jiang-Tao Wang
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Abstract

Lithium is a fragile but crucial chemical element in the universe, exhibits interesting and complex behaviors. Thanks to the massive spectroscopic data from the Large Sky Area Multi-Object Fiber Spectroscopic Telescope (LAMOST) medium-resolution survey (MRS), we can investigate the lithium abundances in a large and diverse sample of stars, which could bring vital help to study the origin and evolution of lithium. In this work, we use the Li 6,707.8 {\AA} line to derive the lithium abundance through a template-matching method. A catalog of precise lithium abundance is presented for 795,384 spectra corresponding to 455,752 stars from the LAMOST MRS Data Release (DR) 9. Comparing our results with those of external high-resolution references we find a good consistency with a typical deviation of {\sigma} A(Li) ~ 0.2 dex. We also analyze the internal errors using stars that have multiple LAMOST MRS observations, which will reach as low as 0.1 dex when the signal-to-noise ratio (S/N) of the spectra > 20. Besides, our result indicates that a small fraction of giant stars still exhibit surprisingly high amount of lithium contents, and 967 stars are identified as Li-rich giants with A(Li) > 1.5 dex, accounting for ~ 2.6% of our samples. If one takes into account the fact that nearly all stars deplete lithium during the main sequence, then the fraction of Li-rich stars may exceed 2.6% much. This new catalog covers a wide range of stellar evolutionary stages from pre-main sequence to giants, and will provide help to the further study of the chemical evolution of lithium.

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Ming-Yi Ding, Jian-Rong Shi, Hong-liang Yan, Chun-Qian Li, Qi Gao, Tian-Yi Chen, Jing-Hua Zhang, Shuai Liu, Xiao-Jin Xie, Yao-Jia Tang, Ze-Ming Zhou, Jiang-Tao Wang. 2024-03-04. Lithium Abundances from the LAMOST Med-Resolution Survey Data Release 9. https://arxiv.org/abs/2403.01815

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