Contact and near-contact binary systems

BVRIsub(c) photometry is presented for three late-type contact binaries: EZ Hydrae, AD Phoenicis and RS Columbae. EZ Hydrae is identified as a W-type system of orbital period 0.45 day, while AD Phoenicis and RS Columbae are probably A-type systems, with orbital periods of 0.38 and 0.67 day, respectively. Although a value for the mass ratio of EZ Hydrae had been obtained from spectroscopic observations, no photometric solution could be obtained because of severe 'disturbances' in its light curve. On the other hand, photometric solutions were obtained for AD Phoenicis and RS Columbae, but these were very insensitive to mass ratio, which tended toward the unlikely value of unity. (author)