The evolution of C and O abundances in stellar populations
  Carbon and oxygen abundances in F and G main-sequence stars ranging in
metallicity from [Fe/H] = -1.6 to +0.5 are determined from a non-LTE analysis
of CI and OI atomic lines in high-resolution spectra. Both C and O are good
tracers of stellar populations; distinct trends of [C/Fe] and [O/Fe] as a
function of [Fe/H] are found for high- and low-alpha halo stars and for thick-
and thin-disk stars. These trends and that of [C/O] provide new information on
the nucleosynthesis sites of carbon and the time-scale for the chemical
enrichment of the various Galactic components.
