Chemical Abundances of Galactic Cepheid Variables that Calibrate the P-L Relation

We have completed spectroscopic studies of 23 Galactic cepheids to determine possible metallicity effects on measuring the zero point of the P-L relation. We find a spread of 0.4 dex in [Fe/H], which is not the result of either observational scatter or of a metallicity gradient within the Galactic disk. We find a smaller, less significant spread of 0.2 dex in [alpha /Fe]. Our results are robust, determined by constancy of [Fe/H] derived at differing temperatures throughout the pulsational cycle, and abundances of two dwarfs compared to U Sgr in the cluster M 25. We discuss briefly the effect of metallicity on the P-L relation. We also argue that EV Sct and QZ Nor are overtone pulsators, and that the latter is not a member of the cluster NGC 6067.