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Paper: Metallicity effects on synthetic Cepheid Period-Luminosity relations
Volume: 167, Harmonizing Cosmic Distance Scales in a Post-Hipparcos Era
Page: 288
Authors: Musella, I.
Abstract: On the basis of new theoretical results (Bono, Marconi & Stellingwerf, 1998, hereafter BMS; Bono, Caputo, Castellani & Marconi, 1998, hereafter BCCM) useful predictions concerning the Period-Luminosity (PLR) and Period-Luminosity-Color (PLCR) relations both for optical and infrared magnitudes are presented. It is shown that, following the dependence of the instability strip on metallicity, there is a non negligible dependence of the PLRs and PLCRs on the metallicity of the pulsating stars, mainly for optical bands. In particular theoretical results predict a dependence of the PLR on metals which is reversed with respect to current empirical evaluations (see for instance Gould 1994, Sasselov et al. 1997, Kennicutt et al. 1998, hereafter K98). To give a possible explanation for this discrepancy the typical observational procedures used to estimate extragalactic distances through Cepheid PLRs are here tested, with the aim of disentangling, if possible, the reddening and metallicity effects. To this purpose, synthetic PLRs for different metallicities were produced and treated as typical observational samples.
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