Metallicity-Dependent Transformations for Red Giants with Synthetic Colours of UBV and ugr

Abstract

We present metallicity-dependent transformation equations between UBV and SDSS ugr colours for red giants with synthetic data. The ranges of the colours used for the transformations are 0.400 = -0.01 and sigma(u - g)(0) = 0.07 mag, respectively. We showed that interstellar reddening plays an important role on the derived colours. The transformations can be applied to clusters as well as to field stars. They can be used to extend the colour range of the red giants in the clusters which are restricted due to the saturation of the SDSS data.