CARBON ABUNDANCES IN G-DWARFS

Model atmospheres and synthetic spectra are used to calibrate photoelectric measurements of the C2 Swan bands in spectra of G dwarfs. The assumption that the iron-to-hydrogen ratio can be obtained from the ultraviolet excess and that the abundances of carbon, oxygen and iron vary in unison lead to excellent agreement between prediction and observation for the majority of stars. Super-metal-rich dwarfs are apparent exceptions to the rule, having either small carbon excesses or oxygen deficiencies if the currently-accepted iron abundances are correct. © 1976 Royal Astronomical Society.