Identify ~20,000 Li-rich Giants in the LAMOST Low-Resolution Survey

TL;DR

This study systematically identifies over 20,000 lithium-rich giant stars from the LAMOST low-resolution survey, creating a large, homogeneous catalog to advance understanding of stellar evolution and lithium enrichment.

Contribution

It introduces a robust method for detecting Li-rich giants using low-resolution spectra and provides the largest homogeneous catalog of such stars to date.

Findings

Over 20,000 Li-rich giants identified, about 2.5% of all giants in the sample.

Validated lithium abundances show good agreement with high-resolution studies.

The catalog enables detailed analysis of Li-rich giant occurrence across evolutionary stages.

Abstract

Li-rich giants serve as valuable tracers of stellar evolution and surface enrichment processes, for which a statistically large and homogeneous sample is crucial. Using the massive low-resolution ($R \sim 1800$) spectroscopic dataset from the Large Sky Area Multi-Object Fiber Spectroscopic Telescope (LAMOST) survey, we systematically search for Li-rich giants by determining their stellar lithium abundances through template matching of the Li I 6708 {\AA} absorption line with a grid of synthetic spectra generated from ATLAS9 model atmospheres. The derived abundances are validated against previous high-resolution studies, showing good consistency with a mean absolute error of about 0.15 dex. Therefore, we adopt a threshold of $A(\rm{Li}) > 1.65$ dex to select Li-rich candidates, followed by visual inspection to ensure the reliability of each detection. Eventually, more than 20,000 Li-rich giants are identified, corresponding to approximately 2.5% of all giants in LAMOST DR9. We also investigate the occurrence rate of Li-rich giants in different evolutionary stages. This work presents a large and homogeneous catalog of Li-rich giants derived from the LAMOST low-resolution survey, which provides a reliable and valuable dataset for future studies of stellar evolution and lithium enrichment in evolved stars.