How Metal Shapes the Light of Cepheids: A Stellar Evolution View of the Leavitt Law

This study uses stellar evolution models to show how metallicity affects the brightness-period relation (Leavitt Law) of Cepheid stars. The authors find that lower-metallicity Cepheids have steeper and slightly brighter period-luminosity relations. Their predictions match key observational data and support current methods for measuring the Hubble constant, especially those using reddening-free magnitudes.