A calibration of Geneva photometry for B to G stars in terms of Teff, log g and [M/H]

Abstract

We have used recent Kurucz models and numerous standard stars to improve the calibration of the Geneva photometric system proposed a few years ago. A new photometric diagram for the classification of intermediate stars (8500 ≤ Teff ≤ 11000 K) is proposed and fills a gap that the previous calibration had left open. Evidence is given for a clear inadequacy of the new Kurucz models in the region of the parameter space where convection begins to take over radiation in the star's atmosphere. This problem makes the determination of the surface gravity difficult, but leaves that of the other parameters apparently unaffected. The determination of metallicity is considerably improved, thanks to the homogeneous spectroscopic data published recently by Edvardsson et al. (1993). Instead of showing the traditional diagrams, we chose to publish the diagrams of the physical parameters with the inverted grids inside, i.e. the lines of constant photometric parameters.