A new empirical metallicity calibration for Vilnius photometry

Abstract

We present a new calibration of the seven-color Vilnius system in terms of [Fe/H], applicable to F-M stars in the metallicity range -2.8<[Fe/H]<+0.5. We employ a purely empirical approach, based on ~1000 calibrating stars with high-resolution spectroscopic abundance determinations. It is shown that the color index P-Y is the best choice for a most accurate and sensitive abundance indicator for both dwarf and giant stars. Using it, [Fe/H] values can be determined with an accuracy of $\pm$0.12 dex for stars of solar and mildly sub-solar metallicity and $\pm$0.17 dex for stars with [Fe/H]<-1. The new calibration is a significant improvement over the previous one used to date.