Chemical Evolution of the Galactic Disk: Evidence for a Gradient Perpendicular to the Galactic Plane

Abstract

view Abstract Citations (93) References (172) Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS Chemical Evolution of the Galactic Disk: Evidence for a Gradient Perpendicular to the Galactic Plane Piatti, Andres E. ; Claria, Juan J. ; Abadi, Mario G. Abstract An improved DDO abundance calibration presented in a previous paper is used to derive overall [Fe/H] abundances for 233 red giants in a sample of 63 open clusters with a wide range of ages. Membership of the giants in each cluster is confirmed by using velocity, astrometric, and photometric information. The newly derived abundances allow us: (1) to confirm the absence of a global age-metallicity relation for the entire open cluster sample; (2) to define a homogeneous abundance scale for the Galactic open cluster system. If this scale is adopted, a radial abundance gradient (∂[Fe/H]/∂Rgc = -0.07 dex kpc-1) as well as a steeper abundance gradient perpendicular to the Galactic plane (∂[Fe/H]/∂|Z| = -0.34 dex kpc-1) are found. Orbital motions for a subsample of 9 open clusters with sufficiently good distances and kinematical data are calculated by assuming a Miyamoto-type gravitational potential for the Galaxy. The dynamical evolution of each cluster is computed backwards for a time interval equal to its age and some relevant parameters of each cluster orbit are derived. It is found that both the radial and Z gradients determined from the observed cluster positions are very close to the paleogradient ones, namely, the gradients in metallicity of the gas out of which the clusters have been generated. Publication: The Astronomical Journal Pub Date: December 1995 DOI: 10.1086/117731 Bibcode: 1995AJ....110.2813P Keywords: GALAXY: EVOLUTION; GALAXY: ABUNDANCES full text sources ADS | data products SIMBAD (162)