2018MNRAS.475.2675W

We report the analysis of time series of infrared JHK_s photometry of the dwarf nova V2051 Oph in quiescence. We modelled the ellipsoidal variations caused by the distorted mass-donor star to infer its JHK_s fluxes. From its infrared colours, we estimate a spectral type of M(8.0 ± 1.5) and an equivalent blackbody temperature of T_BB = (2700 ± 270) K. We used the Barnes & Evans relation to infer a photometric parallax distance of d_BE = (102 ± 16) pc to the binary. At this short distance, the corresponding accretion disc temperatures in outburst are too low to be explained by the disc-instability model for dwarf nova outbursts, underscoring a previous suggestion that the outbursts of this binary are powered by mass-transfer bursts.