  Although carbon is, together with oxygen and nitrogen, one of the most
important elements in the study of galactic chemical evolution its production
sites are still poorly known and have been much debated (see e.g. Gustafsson et
al. 1999; Chiappini et al. 2003). To trace the origin and evolution of carbon
we have determined carbon abundances from the forbidden [C I] line at 8727 A
and made comparisons to oxygen abundances from the forbidden [O I] line at 6300
A in a sample of 51 nearby F and G dwarf stars. These data and the fact that
the forbidden [C I] and [O I] lines are very robust abundance indicators (they
are essentially insensitive to deviations from LTE and uncertainties in the
stellar parameters, see, e.g., Gustafsson et al. 1999; Asplund et al. 2005)
enable us to very accurately measure the C/O ratio as well as individual C and
O abundances. Our first results indicate that the time-scale for the main
source that contribute to the carbon enrichment of the interstellar medium
operate on the same time-scale as those that contribute to the iron enrichment
(and can possibly be AGB stars...)
