Absolute Magnitude Calibration for W UMa-Type Systems Based on Gaia Data

Abstract

Tycho-Gaia Astrometric Solution (TGAS) parallax data are used to determine absolute magnitudes $M_V$ for 318 W~UMa-type (EW) contact binary stars. A very steep (slope $\simeq -9$), single-parameter ($\log P$), linear calibration can be used to predict $M_V$ to about 0.1 -- 0.3 mag over the whole range of accessible orbital period, $0.22<P<0.88$ days. A similar calibration for the most common systems with $0.275<P<0.575$ days predicts $M_V$ values to about 0.06 -- 0.16 mag. For orbital period values both shorter and longer than the central range, the period dependence is respectively steeper and shallower, i.e.\ the binaries are fainter in $M_V$ than predicted by the whole-range, linear law. The steepness of the relation for short-period systems implies important consequences for the detectability of the faintest binaries defining the short-period cut-off of the period distribution. Although the scatter around the linear $\log P$-fit is fairly large (0.2 -- 0.4 mag), the current data do not support the inclusion of a $B-V$ color term in the calibration.

17 pages, 4 figures, accepted by AJ 2 Aug.2017

References in corpus (9)

• The Gaia mission
• Gaia Data Release 1. Summary of the astrometric, photometric, and survey properties
• Contact Binaries with Additional Components.I. The Extant Data
• Contact Binaries with Additional Components. II. A Spectroscopic Search for Faint Tertiaries
• Contact binaries with additional components. III. The adaptive optics detections
• The short period end of the contact binary period distribution based on the All Sky Automated Survey (ASAS)
• Luminosity function of contact binaries based on the ASAS survey
• Contact Binaries as Viable Distance Indicators: New, Competitive (V)JHKs Period-Luminosity Relations
• Time sequence spectroscopy of AW UMa. The 518 nm Mg I triplet region analyzed with Broadening Functions

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• Zwicky Transient Facility and Globular Clusters: the Period-Luminosity and Period-Luminosity-Color Relations for Late-Type Contact Binaries