The third version of the Gaia FGK Benchmark Stars

Abstract

The Gaia FGK Benchmark Stars (GBS) are reference stars carefully selected for the calibration and the validation of atmospheric parameters massively determined from large-scale spectroscopic surveys. Their Teff and logg are determined independently of spectroscopy, through the fundamental relations based on angular diameters, bolometric fluxes, parallaxes and masses. An initial version of the GBS comprising 34 stars was presented by \cite{hei15}. We now introduce the third version, GBS V3, which comprises ∼200 stars