METALLICITIES OF 2 DISTANT GLOBULAR-CLUSTERS FROM SPECTRA OF MODERATEDISPERSION

We have used model atmospheres and spectrum synthesis to analyze mediu m resolution, moderate signal-to-noise, blue spectra of three stars in each of the globular clusters NGC 7006 and NGC 6229 for metallicity a nd carbon abundance. Both clusters are known to have intermediate meta llicity, but NGC 7006 has a reddish horizontal branch, while NGC 6229 has a blue horizontal branch. We find that [M/H] = -1.6 for NGC 7006 a nd [M/H] = -1.4 for NGC 6229, with uncertainties near +/-0.1. In NGC 7 006 carbon is depleted, presumably by CN cycling, so that [C/Fe] = -0. 71. Our [C/Fe] ratio, as derived for stars with T-eff similar to 4200 K, agrees with the [C/Fe] ratio found by Friel et al. for stars with T -eff between 4500 and 4700 K. This shows that the stars in NGC 7006 ha ve not suffered additional mixing as they advance up the giant branch from 4700 K to the red giant tip. For NGC 6229 we derive [C/Fe] = -0.5 6. We find evidence for a scatter in [C/Fe], indicating differing degr ees of carbon depletion from star to star.