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Detection of superhumps in the new CV TSS J022216.4+412260

The Astronomer's Telegram #658, posted on Nov 17, 2005, announced the discovery by R. Quimby et al. (Univ of Texas and The Nearby Supernova Factory) of an optical transient, based on unfiltered CCD images taken on November 16.1 UT (about 15.5 mag) and November 17.1 (also about 15.5 mag), using the 0.45m ROTSE-IIIb telescope at the McDonald Observatory. The object, named TSS J022216.4+412260, is located at RA = 02h22m16.4s, DEC = +41o22'59.9" (J2000; uncertainty +/- 0.5"). It was not visible in ROTSE-IIIb data from November 15.1 UT (limiting mag about 16.5). A spectrum taken by The Nearby Supernova Factory on November 18.6 UT, with the Supernova Integral Field Spectrograph on the University of Hawaii 2.2-meter telescope, showed it to be a dwarf nova in outburst. The spectra revealed a blue continuum with prominent H-alpha and HeII 4686 emission lines.

I started observations of TSS J022216.4+412260 on Nov 21/22, 2005 at CBA Belgium Observatory, using a 0.35-m f/6.3 telescope and (unfiltered) ST-7XME camera. The session lasted for 1.7 hours (had to be interrupted due to clouds), and revealed a superhump modulation.

Light curve of TSS J022216.4+412260 obtained a CBA Belgium Observatory on Nov 21/22, 2005

A period analysis using Peranso's ANOVA method, yields a superhump period of 0.059 +/- 0.007 d, with an amplitude of 0.3 mag. The object was around mag 15.9 during my observations.

My findings are in good agreement with results published by the Kyoto team, who independently derived a similar superhump period, based on their observations.

TSS J022216.4+412260 is amongst the shortest superhumping dwarf novae presently known (e.g., Var Vul 05 has a superhump period of 0.058 +/- 0.003 d).