2023MNRAS.523.5230L

This paper investigates the problem of estimating three stellar atmospheric physical parameters and 13 elemental abundances for medium-resolution spectra from Large Sky Area Multi-Object Fiber Spectroscopic Telescope (LAMOST). Typical characteristics of these spectra are their huge scale, wide range of spectral signal-to-noise ratio (S/N), and uneven distribution in parameter space. These characteristics lead to unsatisfactory results on the spectra with low temperature, high temperature, or low metallicity. To this end, this paper proposes a stellar parameter estimation method based on multiple regions (SPEMR) that effectively improves parameter estimation accuracy. On the spectra with S/N ≥ 10, the precisions are 47 K, 0.08 dex, 0.03 dex, respectively, for the estimations of (T_eff, $\log \, g$, and $\rm [Fe/H]$), 0.03-0.06 dex for elements C, Mg, Al, Si, Ca, Mn, and Ni, 0.07-0.13 dex for N, O, S, K, and Ti, while that of Cr is 0.16 dex. For the reference of astronomical science researchers and algorithm researchers, we released a catalogue for 4.19 million medium-resolution spectra from the LAMOST DR8, experimental code, trained model, training data, and test data.