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There is an increasing body of evidence that suggests that Be disks are welldescribed by the Viscous Decretion Disk (VDD) model according to which theformation and structure of the disk depend on the kinematic viscosity of thegas. However, most observational tests of the VDD to-date were done for systemsthat do not display strong temporal variability. From this analysis we (1)obtain a realistic physical model of the circumstellar environment; (2) measurethe viscosity parameter of the gas, both during the formation and dissipationphases of the disk; (3) obtain a reliable estimate of the stellar mass andangular momentum loss rates during outburst. Our simulations suggests that theVDD model adequately describes the structural evolution of the disk.Furthermore, our analysis allowed us to determine the viscosity parameter a, aswell as the net mass and angular momentum (AM) loss rates. We find that a isvariable, ranging from 0.1 to 1.0, not only from cycle to cycle but also withina given cycle. Additionally, build-up phases have larger values of a than thedissipation phases. We also find that, contrary to what is generally assumed,during dissipation the outward AM flux is not necessarily zero, meaning that{\omega} CMa does not experience a true quiescence but, instead, switchesbetween a high AM loss rate state to a low AM loss rate one during which thedisk quickly assumes an overall lower density but never zero. We confront theaverage AM loss rate with predictions from stellar evolution models forfast-rotating stars, and find that our measurements are smaller by more thanone order of magnitude. The model developed using the V-band photometry as aconstraint was applied to several other observables. Overall, the results ofthis multi-technique study were very positive, with a good match for multi-bandphotometry, polarization, and most spectroscopic characteristics.

A Multi-technique Study of the Dynamical Evolution of the Viscous Disk around the Be Star {\omega} CMa