Study of the effect of metallicity on the amplitudes of Cepheids

TL;DR

This study investigates how metallicity influences the amplitudes of Galactic Cepheids, revealing that certain amplitude ratios are unaffected by metallicity, while some observed dependencies contradict theoretical expectations.

Contribution

It provides empirical analysis of metallicity effects on Cepheid amplitudes and compares observed period-amplitude relations with theoretical models.

Findings

Photometric amplitude ratio $A_I/A_V$ is independent of metallicity.

Observed period-amplitude dependence does not match theoretical predictions.

Galactic metallicity distribution of Cepheids is characterized.

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.