Automatic determination of stellar atmospheric parameters and construction of stellar spectral templates of the Guoshoujing Telescope (LAMOST)

A number of spectroscopic surveys have been carried out or are planned to study the origin of the Milky Way. Their exploitation requires reliable automated methods and softwares to measure the fundamental parameters of the stars. Adopting the ULySS package, we have tested the effect of different resolutions and signal-to-noise ratios (SNR) on the measurement of the stellar atmospheric parameters (effective temperature T_eff, surface gravity log g, and metallicity [Fe/H]). We show that ULySS is reliable for determining these parameters with medium-resolution spectra (R ~ 2000). Then, we applied the method to measure the parameters of 771 stars selected in the commissioning database of the Guoshoujing Telescope (LAMOST). The results were compared with the SDSS/SEGUE Stellar Parameter Pipeline (SSPP), and we derived precisions of 167 K, 0.34 dex, and 0.16 dex for T_eff, log g and [Fe/H] respectively. Furthermore, 120 of these stars are selected to construct the primary stellar spectral template library (Version 1.0) of LAMOST, and will be deployed as basic ingredients for the LAMOST automated parametrization pipeline.