Cowan, John AST 96-18332 Dr. Cowan will continue research into the formation, evolution, and age of the heavy elements, with particular emphasis on the formation of the neutron capture s- and r-process elements. His research utilizes a dynamic r-process code, which incorporates the most current nuclear data, in combination with observational data for the most metal-poor stars of the Galactic halo. His theoretical studies will define the environments, both nuclear and astrophysical, in which these heavy elements were formed and provide insight into the conditions that existed early in the history of the Galaxy and into the nature of the progenitors of the halo stars. Closely related efforts to investigate the r- and s-process production as a function of stellar metallicity will offer constraints on early Galactic timescales for stellar formation. Dr. Cowan will also continue studies of the use of long-lived radioactive chronometers (especially Th and U) and the development of more realistic chemical evolution models to provide more accurate estimates of the age of the Galaxy, and constrain cosmological age estimates. ***
