Metallicity of the young halo globular cluster Ruprecht 106

Medium resolution spectra of 3 stars have been used to determine the metallicity of the globular cluster Ruprecht 106. On the basis of a code developed by Cayrel et al. (1991), we computed a grid of synthetic spectra in order to derive the metallicity of these stars. We found an abundance of [Fe/H] = -1.6 +/- 0.25 which, although not formally at variance with the estimate of metallicity based on the slope of the RGB ([Fe/H] = -1.9 +/- 0.2) raises some puzzling questions concerning the true metallicity of this cluster.