New radiation driven wind solutions including stellar rotation:: Applicability to Be stars

The theory of radiative-line driven wind including stellar rotation is re-examined. After a suitable change of variables, new analytical equations for the mass loss rate and position of the critical point are derived. A non-linear equation for the position of the critical point is obtained, in order to solve it, a beta -field is used, and in addition to the standard CAK critical point two other critical points as function of star's rotational speed (V-phi) are founded. When the stellar rotation velocity is approximate or greater than 0.8 x Vbreak-up, the CAK critical point is located far away in the wind (r > 4R(*)) and there we have again only one critical point. Numerical solutions from this new critical point are obtained, they have very low terminal velocities (approx. 400 km/sec). The applicability of this new solution in the frame of Be stars are discussed.