Absolute Calibration of the PL-Relations for the Classical Cepheids Based on the HIPPARCOS Parallaxes and the Distances of the Magellanic Clouds

Abstract

The zero points of the period-luminosity relations for the classical cepheids are calibrated based on the HIPPARCOS parallaxes of these stars. The calibrations are used to determine the distance moduli of the LMC and SMC: DM_LMC = 18^m.569 ± 0^m.117 and DM_SMC = 19^m.070 ± 0^m.119, respectively. It turns out that a calibration of the PL relations based on the distances of 25 FU classical cepheids in the galaxy by Gieren et al. yields a distance scale that is shorter by approximately 0^m.20 than the calibrations based on the HIPPARCOS parallaxes.