γ Cassiopeiae revisited by spectrally resolved interferometry.

We present a model for the Be star γ Cassiopeiae which is based on spectroscopic and interferometric data collected with the Grand Interferometre a 2 Telescopes (GI2T) in southern France. Our model assumes a standard radiation-driven wind in the polar regions. Using a parametrized and axi-symmetric scheme we deduce the wind for other stellar latitudes. The comparison of computed and observed Hα profiles during October and November 1993, together with the interferometric measurements, allows us to constrain both the density and velocity relationships present in the equatorial plane. For the first time we have shown that a model of a radiative wind driven by optically thin lines can account well for our angular/spectral resolution data.