BELGIAN ASTRONOMICAL SOCIETY V.V.S. - Working Group Variable Stars Cataclysmic Variables Circular No.161 1998, February 01 Ed.: T. Vanmunster, Walhostraat 1A, 3401 Landen, BELGIUM Internet: tvanmuns@innet.be TEL. 32-11-831504 CVC Web Page : http://www.astro.columbia.edu/~cba/cvc =================================================================== SBS 1017+533 [UGSU, 13? - 16?] ============================== Peter Garnavich recently reported his detection of an outburst of SBS 1017+533 [VSNET alert 1441]. He also reported spectral observations, showing broad Balmer absorption lines, but weak Halpha emission. Unfiltered CCD photometry by Tonny Vanmunster, CBA Belgium Observatory, on 1998, January 31, using a 0.25-m telescope and ST-7 CCD camera, reveals the existence of a periodic modulation in this system, which has the typical signature of a superhump. It therefore is most likely that SBS 1017+533 is a new member of the SU UMa-type cataclysmic variables ! Our observations were made under quite unfavourable conditions (strong windws), during a 7.8h observing session and show a periodic signal at 0.069 +/- 0.001 d, with a mean semi-amplitude of 0.11 mag, after heliocentric correction and removal of a linear trend of decline (period determined using the PDM method). SBS 1017+533 is located at RA = 10h20m26.65s and decl = +53d04'32.6" (Epoch J2000.0). Follow-up time-series CCD photometry is highly recommended. Editorial Absence ----------------- Please note that the Editor will be absent in the period from February 9th till February 17th, 1998. Tonny Vanmunster