Abstract

We present a photometric and spectroscopic study of HD 50526, an ellipsoidal binary member of the group Double Periodic Variable stars. Performing data mining in photometric surveys and conducting new spectroscopic observations with several spectrographs during 2008-2015, we obtained orbital and stellar parameters of the system. The radial velocities were analyzed with the genetic PIKAIA algorithm, whereas Doppler tomography maps for the H alpha and H beta lines were constructed with the Total Variation Minimization code. An optimized simplex algorithm was used to solve the inverse problem adjusting the light curve with the best stellar parameters for the system. We find an orbital period of 6.(d)701 +/- 0.(d)001 and a long photometric cycle of 191 +/- 2 days. We detected the spectral features of the coldest star and modeled it with a log g = 2.79 +/- 0.02 dex giant of mass 1.13 +/- 0.02M(circle dot) and effective temperature 10500 +/- 125 K. In addition, we determine a mass ratio q = 0.206 +/- 0.033 and that the hot star is a B-type dwarf of mass 5.48 +/- 0.02M(circle dot). The V-band orbital light curve can be modeled including the presence of an accretion disk around the hotter star. This fills the Roche lobe of the hotter star and has a radius 14.74 +/- 0.02 R-circle dot and the temperature at the outer edge is 9400 K. Two bright spots located in the disk account for the global morphology of the light curve. The Doppler tomography maps of H alpha and H beta reveal complex structures of mass fluxes in the system.