HEAVY-ELEMENT NUCLEOSYNTHESIS AND GALACTIC CHEMICAL EVOLUTION

Two aspects of the relation between heavy-element nucleosynthesis and galactic chemical evolution are examined. In the first part, observed heavy-element abundance ratios in the halo and the disk are compared w ith one-zone models of galactic chemical evolution. These comparisons provide useful insight into the kinds of stellar environments responsi ble for r- and s-process nucleosynthesis. In the second part, we const ruct a schematic model for the formation and evolution of the Galaxy b ased upon the multiple mergers of protogalactic clouds within the expa nding and collapsing halo. We analyze the various cosmochronometers wi thin this model and show that the apparent differences between the max imum globular-cluster ages, the white-dwarf cooling age, and the nucle ar chronometric ages can be interpreted as indicators of different asp ects of the Galaxy formation process.