THE RELATION BETWEEN THE INITIAL AND FINAL MASSES OF STARS WITH DIFFERENT CHEMICAL-COMPOSITIONS

We present the results of calculations for the relations between the i nitial and final masses M-i-M-f of low- and moderate-mass stars for va rious initial heavy-element abundances Z. For Z = 0.02 and Z = 0.001, the resulting differences in the final masses for white dwarfs reach 0 .1M. for initial masses from 1.5 to 4M.. These differences are Primari ly due to the dependence of the initial masses of the carbon-oxygen co res of asymptotic giant branch stars on their chemical compositions. W e study the roles of various assumptions about mass loss of stars in t he final stages of their evolution. The population of white dwarfs is modeled, and their mass distribution is obtained for various assumptio ns about the initial chemical composition of the stars.