On Accretion in the Polar V379 Vir

Abstract

Based on optical and infrared survey data spanning \(\approx 20\) years of observations, the long-term variability of the polar V379 Vir with a brown dwarf secondary has been studied. By modeling the spectral energy distribution, we constrain the white dwarf’s mass to \(M_{1}=0.61\pm 0.05\;M_{\odot}\) and its effective temperature to \(T_{\textrm{eff}}=10\,930\pm 350\text{ K}\). Near-infrared photometry yields a donor radius of \(R_{2}=0.095\pm 0.018\;R_{\odot}\) and temperature \(T_{\textrm{eff}}=1600\pm 180\text{ K}\). Modeling of the cyclotron emission from the accretion spot, detected with the Spitzer infrared telescope, gives an accretion rate of \(\dot{M}\approx 3\times 10^{-13}\;M_{\odot}/\textrm{yr}\). This rate is consistent with polars in a low accretion state, but significantly higher than expected from wind-driven mass transfer.