A New Empirical Metallicity Calibration for Vilnius Photometry

We present a new calibration of the seven-color Vilnius system in terms of [Fe/H], applicable to F--M stars in the metallicity [Fe/H] range from --2.8 to +0.5. We employ a purely empirical approach, based on about 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 ±0.12 dex for stars of solar and mildly sub-solar metallicity and ±0.17 dex for stars with [Fe/H] less than --1. The new calibration is a significant improvement over the previous one used to date.