METHODS OF THE ATMOSPHERIC PARAMETERS DETERMINATIONS

Abstract

Different methods of fundamental parameters determinations - effective temperature (Teff ), surface gravity (log g), metallicity ([M/H]), radius R=Ro, mass M=Mo, luminosity for B to K stars are briey described. They include both model-independent' methods such as total ux measurements + interferometry; asteroseismology (Te , R=R, log g, M=M); and 'model-dependent'
methods. The latter methods are based on the modelling of different observablessuch as photometric indexes, stellar spectra, stellar flux ( Infra Red Fluxmethod - IRFM). A special attention is paid to spectroscopic methods. The rst one is based on equivalent width measurements and excitation/ionization equilibrium. The second method is 'Spectroscopy Made Easy' (SME) package which ts the calculated spectrum to the observed one varying the global stellar parameters (Teff , log g, [M/H] ) and parameters dening spectral line shape (t, microturbulent and macroturbulent velocities). Although SME originally was developed for massive parameter determinations in F-G-K stars hosting planets, it is successfully working for B and A stars, in particular SME version that includes NLTE analysis.