Study of the effect of metallicity on the amplitudes of Cepheids

Abstract

Results concerning the dependence of photometric and radial velocity amplitudes on metallicity are presented based on about 200 Galactic classical Cepheids pulsating in the fundamental mode. The Galactic distribution of the [Fe/H] value of Cepheids is also studied. We show that the photometric amplitude ratio $A_\mathrm{I}/A_\mathrm{V}$ is independent of metallicity. The observed dependence of this ratio on the pulsation period does not correspond to the theoretical predictions.