Anchors for the Cosmic Distance Scale: the Cepheids U Sgr, CF Cas and CEab Cas
astro-ph.GA
/ Authors
D. Majaess, G. Carraro, C. Moni Bidin, C. Bonatto, L. Berdnikov, D. Balam, M. Moyano, L. Gallo, D. Turner, D. Lane
and 4 more authors
/ Abstract
New and existing X-ray, UBVJHKsW(1-4), and spectroscopic observations were analyzed to constrain fundamental parameters for M25, NGC 7790, and dust along their sight-lines. The star clusters are of particular importance given they host the classical Cepheids U Sgr, CF Cas, and the visual binary Cepheids CEa and CEb Cas. Precise results from the multiband analysis, in tandem with a comprehensive determination of the Cepheids' period evolution (dP/dt) from ~140 years of observations, helped resolve concerns raised regarding the clusters and their key Cepheid constituents. Specifically, distances derived for members of M25 and NGC 7790 are 630+-25 pc and 3.40+-0.15 kpc, respectively.