David Boyd, Christopher Lloyd, Robert Koff, Thomas Krajci, Bart Staelss Jerrold Foote, William Goff, Toony Vanmunster, Lewis Cook & Joseph Patterson

摘要

We present analysis and results of a coordinated CCD photometry campaign to observe the 2006 June superoutburst of the cataclysmic variableVI3l6 Cygni, involving eight longitudinally-distributed observers.The outburst peaked at magnitude 15.03 on 2006 June 10, declined at a rate of 0.14 mag/day, lasted 11 days and had an amplitude above quiescence of 2.4 magnitudes.We detected common superhumps for the first time, thereby confirming that V1316 Cyg is a member of the UGSU class of dwarf novae. We observed a transition to late superhumps two-thirds of the way through the outburst with an associated phase shift of 0.50 + 0.06 cycles.The mean common superhump period before this transition was 0.07685 ± 0.00003d and the mean late superhump period following the transition was 0.07654 ± 0.00002d.The common superhump period decreased at a rate dP/dt = -5.1 ± 1.7 * 10~5 per cycle. At the onset of late superhumps, there was a transient shift in power from the superhump fundamental frequency to its first harmonic and back again. We detected an orbital period of 0.0740 ± 0.0002d giving a fractional superhump period excess of 0.038 ± 0.003 and a mass ratio of 0.167 + 0.010. A scalegram analysis of the flickering behaviour ofV 1316 Cyg found that the a and Z parameters characterising flickering changed significantly during the superoutburst. We also found flickering to be at a relatively much lower level at the beginning of the superoutburst and during two 'normal' outbursts.