Superhump periods in the UGSU-type dwarf nova SDSSp J082409.73+493124.4

Abstract

We present observations and analysis of the first reported superoutburst of the dwarf nova SDSSp J082409.73+493124.4 during February/March 2007. From a maximum observed magnitude of 15.4C it declined at 0.09 mag/d for 7 days, flattened out around magnitude 16 for a further 5 days and then returned rapidly to quiescence at magnitude 19.4. The flattening of the light curve late in the outburst was not associated with a re-growth of superhumps. For the first 5 days we observed common superhumps with period 0.06954(5) d, thus confirming its classification as a UGSU-type dwarf nova. This was followed by a phase transition to late superhumps with period 0.06921(6) d. We found a small but persistent signal at 0.0687(6) d which we interpret as the orbital period.

Accepted for publication in Journal of the British Astronomical Association, 11 pages, 8 figures