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arXiv · 1311.0865

Anchors for the Cosmic Distance Scale: the Cepheids U Sgr, CF Cas and CEab Cas

D. Majaess·G. Carraro·C. Moni Bidin·C. Bonatto·L. Berdnikov·D. Balam·M. Moyano·L. Gallo·D. Turner·D. Lane·W. Gieren·J. Borissova·V. Kovtyukh·Y. Beletsky
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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.

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D. Majaess, G. Carraro, C. Moni Bidin, C. Bonatto, L. Berdnikov, D. Balam, M. Moyano, L. Gallo, D. Turner, D. Lane, W. Gieren, J. Borissova, V. Kovtyukh, Y. Beletsky. 2013-11-04. Anchors for the Cosmic Distance Scale: the Cepheids U Sgr, CF Cas and CEab Cas. https://doi.org/10.1051/0004-6361/201322670

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