Li-rich Giants in LAMOST Survey. III. The Statistical Analysis of Li-rich Giants

Abstract The puzzle of the Li-rich giant is still unsolved, contradicting prediction standard stellar models. Although exact evolutionary stages play a key role in knowledge giants, limited number giants have been observed with high-quality asteroseismic parameters to clearly distinguish stages. Based on LAMOST Data Release 7 (DR7), we applied data-driven neural network method derive for stars, which contain largest giants. red stars are classified into three Red Giant Branch (RGB), Primary Clump (PRC), and Secondary (SRC) relying estimated parameters. In statistical analysis properties (i.e., mass, carbon, nitrogen, distribution, frequency) found that (1) most RGB suggested be descendants pre-RGB and/or result engulfment planet or substellar companions; (2) massive SRC could natural consequence Li depletion from high-mass stars; (3) internal mixing processes near helium flash can account phenomenon richness PRC dominated comparison [C/N] distributions between normal Li-enriched probably depend mass.