1997/10/20 by Slavek M. Rucinski, S. M. Rucinski, H. W. Duerbeck +1 · 162 citations
Physics and Astronomy · #Astro and Planetary Science #Astronomy and Astrophysical Research #Binary number #Binary star #Calibration #Contact binary #Magnitude (astronomy) #Metallicity #Parallax #Stars #Stellar, planetary, and galactic studies #astro-ph
paper · pdf · doi:10.1086/134014
published in Publications of the Astronomical Society of the Pacific 109, 1340 (Institute of Physics) · 17 pages of text, 8 figures (inserted with psfig) and 3 tables; accepted by PASP for the December 1997 issue
arxiv created 1997/10/20 · openalex publication_date 1997/12/01 · arxiv updated 2009/12/01 · openalex created_date 2016/06/24 · openalex updated_date 2026/08/05
Hipparcos parallax data for 40 contact binary stars of the W UMa-type (with errors in MV < 0.5) are used to derive a new, (B-V)-based absolute-magnitude calibration of the form MV = MV(logP,B-V). The calibration covers the ranges 0.26 < (B-V)0 < 1.14, 0.24 < P < 1.15 day, and 1.4 < MV < 6.1; it is based on a solution weighted by relative errors in the parallaxes (2.7% to 24%). Previous calibrations have not been based on such a wide period and color space, and while they have been able to predict MV with sufficient accuracy for systems closely following the well-known period-color relation, the new calibration should be able to give also good predictions for more exotic "outlying" contact binary systems. The main limitations of this calibration are the inadequate quality of the ground-based photometric data, and the restriction to the (B-V) index, which is more sensitive to metallicity effects than the (V-I) index; metallicities are, however, basically unknown for the local W UMa-type systems.