Observations and Analysis of the Field Contact Binary V728 Herculis

The W UMa system V728 Her has been observed photometrically in B, V, and I_C passbands at the RAO over five seasons and spectroscopically at DAO over three seasons to obtain radial velocities. New times of minima are provided and a period analysis confirms previous ephemerides. The light and radial velocity curves were analyzed with the latest University of Calgary enhancements to the Wilson-Devinney program and new solutions found. The best model is that involving a contact system with convective atmospheres. In probing the best solution possible, use was made of the enhanced reflection and second-order limb-darkening calculations available in the 1993 version of the WD program. The mass ratio is found to be 0.1786±0.0023. The contact parameter is found to be f=0.71±0.1l. The masses are determined to be 1.654±0.037 M_sun and 0.295±0.009 M_sun and the radii are l.784±0.0l5 R_sun and 0.867±0.054 R_sun, respectively. The determined temperature difference, T₂ - T₁ is 165±19 K, and the luminosities for components 1 and 2 are 5.5±0.5 L_sun and 1.4±0.3 L_sun, respectively.