SIMBAD references

Radial abundance profiles in galaxy disks are predicted in the framework of the chemical evolution of star-forming viscous disk. Using new calculations of heavy-element yields from Type Ia and Type II supernovae, the oxygen and iron abundances as well as the oxygen-to-iron abundance ratio are derived as a function of radial distance away from the galaxy center, and the results are compared with recent observations in the Galactic disk. The main prediction of the viscous disk model is that both α-elements and iron-peak elements exhibit a small, similar gradient for either stars or gas. We also examine to what extent the bulge is regarded as an inward extension of the disk from a viewpoint of chemical properties. The viscous disk model with a Salpeter initial mass function of stars is found to account for the observed metallicity distribution of K-giant stars in the Galactic bulge.