The preliminary statistical analysis of LAMOST DR10 low resolution AFGK stars based on different metal abundances

Abstract

LAMOST DR10 low resolution catalog (LRC) v1.0 has released 7,478,650 AFGK type stars with corresponding parameters and small parameter errors. These spectra are observed from October 2011 to July 2022. These AFGK stars are a large sample with very small stellar parameter errors, which are very suitable for statistical research work. The stars with [Fe/H] from -2.5 to -2.0, -1.5 to -1.3, and 0.5 to 1.0 were selected as representations for a statistical research. We analyze these stars with the distribution of effective temperature and surface gravity. In addition, we perform a cross-match research between our samples and the red giant branch (RGB) stars and red clump (RC) stars identified by Wang et al. Some low mass stars and medium mass stars are evolved using the stellar evolution code MESA. The calculated theoretical results are compared with the observed statistical data. Most of the stars are main-sequence (MS) stars with log$g$ around 4.0. The other stars are probably RGB stars or RC stars with log$g$ $\le$ 3.0. The very metal-poor stars ([Fe/H] from -2.5 to -2.0) probably are $n$-generation stars with a small value of $n$, which can help us to study the early universe. The stars with [Fe/H] from 0.5 to 1.0 are super metal-rich stars, which probably are $n$-generation stars with a large value of $n$. There is a gap around log$T_{eff}$ = 3.8 for the super metal-rich stars, which corresponds to the MS stars around 1.2 $M_{⨀}$. This will help us to study the formation process of super metal-rich stars. Rich observational data will greatly enhance our understanding to the truth of the universe.