We analyze the V -band photometry data of the Be star \omega CMa , observed during the last four decades .
The data is fitted by hydrodynamic models based on the viscous decretion disk ( VDD ) theory , in which a disk around a fast-spinning Be star is formed by material ejected by the central star and driven to progressively wider orbits by means of viscous torques .
For the first time , we apply the model for both the disk build up and the dissipation phases .
Our simulations offer a good description of the photometric variability in both phases , which suggests that the VDD model adequately describes the disk structural evolution .
Furthermore , our analysis allowed us to determine the viscosity parameter ( \alpha ) of the gas , as well as the net mass loss rate .
We find that \alpha is variable , ranging from 0.1 to 1.0 , and that build up phases have larger values of \alpha than the dissipation phases .
Additionally , we find that , contrary to what is generally assumed , even during quiescence the outward mass flux is never zero , suggesting that the star alternates between a high mass-loss phase ( outburst ) and a low mass-loss phase ( quiescence ) .