The nature of the metal-rich thick disk
  We have traced the Galactic thick disk to its, to date, highest metallicities. Based on high-resolution spectroscopic observations of 187 F and G dwarf stars that kinematically can be associated either with the thin disk (60 stars) or with the thick disk (127 stars), we find that the thick disk stars reach at least solar metallicities, and maybe even higher. This finding is independent of the U_LSR, V_LSR and W_LSR velocities of the stars. 
T. Bensby (1), A.R. Zenn (1), M.S. Oey (1), S. Feltzing (2) ((1) Dept   of Astronomy, University of Michigan, Ann Arbor, USA...