SIMBAD references

A homogeneous set of UBV photometry (354 data points obtained between 1983 and 1998) for the Be/X-ray binary A0535+26=V725 Tau is analysed, aiming to look for possible periodic component(s). After subtraction of the long-term variation it was found that only a≃103^d periodic component remains in the power spectra in both the V and B colour bands. The probability of chance occurrence of such a peak is less than 0.1%. There are no signs of optical variability at the X-ray period (≃111^d). We discuss possible reasons for a 103-day modulation and suggest that it corresponds to a beat frequency of the orbital period of the neutron star and the precession period (≃1400^d) either of an accretion disc around the neutron star or a warped decretion disc around the Be star.