CALIBRATION OF LAMOST STELLAR SURFACE GRAVITIES USING THE KEPLER ASTEROSEISMIC DATA

Abstract

Asteroseismology is a powerful tool to precisely determine the evolutionary status and fundamental properties of stars. With the unprecedented precision and nearly continuous photometric data acquired by the NASA Kepler mission, parameters of more than 10 4 stars have been determined nearly consistently. However, most studies still use photometric effective temperatures ( T eff ) and metallicities ([Fe/H]) as inputs, which are not sufficiently accurate as suggested by previous studies. We adopted the spectroscopic T eff and [Fe/H] values based on the Large sky Area Multi-Object fiber Spectroscopic Telescope (LAMOST) low-resolution spectra ( R ≃ 1800), and combined them with the global oscillation parameters to derive the physical parameters of a large sample of stars. Clear trends were found between and spectroscopic T eff as well as log g , which may result in an overestimation of up to 0.5 dex for the log g values of giants in the LAMOST catalog. We established empirical calibration relations for the log g values of dwarfs and giants. These results can be used for determining the precise distances to these stars based on their spectroscopic parameters.