BV light curves of {gamma} Cas (1997-2011)

These authors also found the V-band cycles to be 30%-40% larger than the B-band cycles. In the present study, we find continued evidence for these variability patterns and for the bimodal distribution of the {Delta}B/{Delta}V amplitude ratios in the long cycles. During the 2010 observing season, {gamma} Cas underwent a mass-loss event ("outburst"), as evidenced by the brightening and reddening seen in our new photometry.

This episode coincided with a waning of the amplitude in the ongoing cycle. The Be outburst ended the following year, and the light-curve amplitude returned to pre-outburst levels. This behavior reinforces the interpretation that cycles arise from a global disk instability.

We have determined a more precise value of the rotation period, 1.215811+/-0.000030 days, using the longer 15-season data set and combining solutions from the V and B light curves. Remarkably, we also find that both the amplitude and the asymmetry of the rotational waveform changed over the years. We review arguments for this modulation arising from transits of a surface magnetic disturbance.

Finally, to a limit of 5 mmag, we find no evidence for any photometric variation corresponding to the {gamma} Cas binary period, 203.55 days, or to the first few harmonics.