F-G-K stars from SDSS-DR5 as tracers of Galactic disks and halo

Spectra of F, G and K stars were selected in the INDO-US, ELODIE, and SDSSDR5 spectroscopic databases to investigate the metallicity distributions and gradients and to derive the Age-Metallicity relation in the different Galactic components. The atmospheric parameters Teff , log g, [Fe/H] and [α/Fe] ratios were derived by comparing synthetic and measured Lick-like spectral indices. Spectroscopic distances were obtained for more than 2000 stars up to z ∼ 6 kpc, and ages were computed for a sub-sample of about 550 stars by using theoretical isochrones with the appropriate [Fe/H] and [α/Fe] values. Full 3D kinematics were derived by means of proper motions and radial velocities and, eventually, stars were divided in four groups belonging to the MW disks and inner and outer Halo according to the stellar orbit properties. The resulting [Fe/H] and [α/Fe] distributions of Thin Disk, Thick Disk, and Halo stars are discussed.