Chemical evolution coefficients for the study of galactic evolution

Abstract

A new evaluation of chemical evolution coefficients has been made using recent stellar evolution and nucleosynthesis data. The role of the low and intermediate mass stars in galactic nucleosynthesis has been emphasized. A significant amount of He-4, C-12 and neutron-rich species is found to be contributed by these stars. Comparison with observed abundances suggests a primary origin of N-14. The simple model of galactic evolution with the new coefficients has been used to derive the ratio of helium to heavy element enrichment in the Galaxy. The new stellar evolution data do not explain the large value of this ratio that has been determined observationally.