Calibrating the Cepheid Period–Wesenheit Relation in the Gaia Bands Using Galactic Open-cluster Cepheids

Abstract Establishing the period–Wesenheit relation requires independent and accurate distance measurements of classical Cepheids (DCEPs). The precise distances provided by associated open clusters independently calibrate relations DCEPs. 51 DCEPs with are compiled using constraints five-dimensional astrometric information. By directly Gaia data release 3 parallaxes, in G band is calibrated as W G = ( − 3.06 ± 0.11 stretchy="false">) log P + 2.96 0.10 . Compared results derived from adopting DCEP parallaxes or moduli, Wesenheit magnitudes based on cluster-averaged exhibit a tighter period. Besides, there systematic offset between observed absolute distant open-cluster their fitted magnitudes. After considering parallax zeropoint correction, can be reduced, yielding probably better ${W}_{G}=(-2.94\pm 0.12)\mathrm{log}P+(-2.93\pm 0.11)$?> 2.94 0.12 2.93