RADIAL VELOCITIES AND METALLICITIES OF RED GIANT STARS IN THE OLD OPEN CLUSTER NGC 7762

We present and discuss radial velocity and the very first metallicity measurements for nine evolved stars in the poorly known old open cluster NGC 7762. We isolated eight radial velocity cluster members and one interloper. Radial velocities are in good agreement with previous studies. NGC 7762 turns out to be of solar metallicity within the uncertainties ([Fe/H] = 0.04 ± 0.12). For this metallicity, the cluster age is 2.5 ± 0.2 Gyr, and falls in an age range where only a few old open clusters are known. With respect to previous studies, we find a larger distance, implying the cluster is located {900}-50+70 pc from the Sun. For most of the elements we measure solar-scaled abundance ratios. We searched the literature for open clusters of similar age in the solar vicinity and found that NGC 7762 can be considered a twin of Ruprecht 147, a similar age cluster located only 300 pc from the Sun. In fact, as well as age, metallicity and abundance ratios are very close to Ruprecht 147 values within the observational uncertainties.