Uvby β photometry of the short-period binary VV Ursae Majoris

We present well-sampled uvby light curves, supplemented by a few β filter measurements, of the Algol binary VV UMa. The light curves are analysed using two different codes to derive the orbital and absolute stellar parameters of this binary. We find reasonably good fits to the light curves and determine the stellar effective temperatures Teff,1 ≃ 9000-9600 K, and Teff,2 ≃ 5300-5600K with a mass ratio q ≃ 0.35. From the light-curve fits we discard the possibility of an anomalous gravity-darkening exponent for the secondary star of this system, as previously suggested. We find evidence of short-term, small-amplitude variations in the brightness of the system. Two periodicities of about 1.10 and 0.51 h seem to be present in the data for at least two different nights, even within the secondary eclipse. This suggests that VV UMa may be a new Algol binary with a low-amplitude variable primary star, but new data collected during longer observing runs are necessary to confirm the pulsating nature of the brightness variations.