Estimate LAMOST hot star's parameters by POLLUX

Abstract

With the highest efficiency of gathering spectra by LAMOST telescope, a large number of spectra have been obtained during commissioning observation, which included a lot of spectra of O type star. It's a difficult task to obtain accurate parameters for hot star, lacking of a good model. Several stellar models, such as MAFAGS, ATLAS, Marcs etc, do not cover the parameter range which temperature exceeds 25000K. POLLUX is a database of synthetic stellar spectra, in which CMFGEN provides atmosphere models for the O type stars (Teff >25000K) [5]. A method of estimating stellar parameters for hot stars is presented in this paper, based on matching LAMOST observed spectra with the theoretical spectra library. We convert the resolution of CMFGEN spectra, which is about 150000 to LAMOST resolution of 2000. By comparing with the CMFGEN template spectra, we can obtain the parameters of observed hot stars. Estimation for the errors of the final parameters shows that low efficiency of LAMOST blue arms of the spectrographs does not affect O type star observations.