Abstract

Full spectrum fitting is known as a reliable method to determine the atmospheric parameters of FGK stars, but its accuracy decreases for either OBA or M stars. We are considering here a method where an observed spectrum is compared to an empirical library of stars with known parameters. Our goal are to quantify the biases on the measurements of the cool stars when using the MILES interpolator published in Prugniel et al. (2011), and to improve these measurements. We generate a new version of the interpolator based on updated atmospheric parameters of MILES stars. The comparison with the literature shows that with this new version, the biases are considerably reduced. The mean bias of the T_eff with repect to literature is of the order of -2K. The mean biases on log g and [Fe/H] are respectively -0.01 and -0.04 dex. The new version of the interpolator is available as a FITS file and the updated table of the adopted parameters for MILES stars is available in electronic form upon request to the author.