Constraining the impact of metallicity on cepheid distances using a refined galactic calibration

Abstract

Evidence is presented implying that the classical Cepheid VI[subscript c] period-Wesenheit function is relatively insensitive to metallicity. The results indicate that variations in chemical composition among Cepheids are a comparatively negligible source of uncertainty for VI[subscript c] Wesenheit-based relations and extragalactic distances, for determinations of H[subscript 0] , and for the selection of a cosmological model. The conclusions rest in part on a Galactic classical Cepheid VI[subscript c] Wesenheit function that has been revised using near-infrared JHK[subscript s] photometry for new and existing clusters containing Cepheid variables.