Abundance structure of the Galactic disk

Abstract

The current knowledge of the abundance structure in the Milky Way is reviewed. Special emphasis is put on recent results for stars with kinematics typical of the thin and the thick disks, respectively, and how these results can, apart from studying the Milky Way also give information about the origin of the elements. Two on-going studies are high-lighted. One that presents new data for stars with kinematics typical of the Hercules stream and one for a small number of dwarf stars high above the galactic plane. These indicate that the thick disk is a homogeneous structure and that the Hercules stream perhaps is part of the metal-rich thick disk. Furthermore, new abundance determinations for Mn for stars with kinematics typical of the thin and the thick disk are presented. From these results the suggestion is that the observed trends for Mn in the Milky Way disks can be explained by metallicity dependent SN II yields. The impacts of surveys on the studies of the elemental abundance trends in the Galaxy are discussed. It is argued that when it comes to furthering our understanding of the abundance structure in the Galactic disk future and ongoing surveys' major impact will be in the form of catalogues to select targets from for high resolution spectroscopic follow-up. For a correct interpretation of the results from these follow-up studies it is important that the surveys have well understood completeness characteristics.