Activity on the M star of QS Vir

Abstract

We report analysis of VRIJH photometry, and phase-resolved optical spectroscopy of the eclipsing DA white dwarf plus dMe dwarf binary QS Vir. Modeling of the photometric data yields an inclination of $i = 74.9\pm0.6$ and a mass ratio of $q = M_2/M_1 = 0.50\pm0.05$. Our Doppler maps indicate the presence of material in the Roche lobe of the white dwarf, at a location near the M star, likely due to accretion from the stellar wind of the M star (as opposed to Roche-lobe overflow accretion). We also constructed images of the brightness distribution of the M star at different epochs which reveal the location of two stable active regions. Doppler tomography shows that the majority of the Hydrogen and Ca II H&K emission originates on the active M dwarf, likely distributed in two preferred activity longitudes, similar to active regions on BY Dra and FK Comae systems.