Metallicity Dependence of the Cepheid Calibration
Abstract
Description
We point out that the absolute magnitude of the Galactic Cepheids, which have been used for local calibrations for Cepheid period-luminosity relation, shows an unexpectedly large metal abundance effect. This indicates that either Cepheids period luminosity relation has a large metallicity dependence, much larger than expected in stellar pulsation models, or the unreddened distances to clusters contain a large systematic error arising from the neglect of the metallicity effect. This effect may introduce an uncertainty of --0.4 to +0.1 mag into the distance to the LMC estimated using the Cepheid PL relation.
8 pages, TeX, 3 PostScript figures, submitted to THE OBSERVATORY
8 pages, TeX, 3 PostScript figures, submitted to THE OBSERVATORY