AAS Meeting #193 - Austin, Texas, January 1999
Session 68. Globular Clusters
Display, Friday, January 8, 1999, 9:20am-6:30pm, Exhibit Hall 1

## [68.10] Elemental Abundances in Five Stars in M54

J.A. Brown (Wash. St. U.), G. Wallerstein, G. Gonzalez (U. Wash.)

We have observed 5 stars in M54, a globular cluster associated with the Sagittarius dwarf galaxy, with the CTIO 4m telescope and echelle spectrometer, in order to measure elemental abundances. We confirm the metallicity [Fe/H] = -1.55 found by other techniques. Two stars show [\alpha/Fe] abundance ratios which are below those in normal" halo stars (that is, [\alpha/Fe] ~ +0.4), but are above solar. The [O/Fe] ratios in these stars are below the solar value, but it is probable that in one star at least the oxygen has been depleted by deep mixing, as the CN bands are strong and the Na and Al abundances are enhanced. The remaining three stars, for which the observations were obtained in August 1998, are being analyzed at the time of this writing, and full results will be presented.