LINE-DRIVEN WINDS REVISITED IN THE CONTEXT OF Be STARS: Ω-SLOW SOLUTIONS WITH HIGH k VALUES

The standard, or fast, solutions of m-CAK line-driven wind theory cannot account for slowly outflowing disks like the ones that surround Be stars. It has been previously shown that there exists another family of solutions-the Omega-slow solutions-that is characterized by much slower terminal velocities and higher mass-loss rates. We have solved the one-dimensional m-CAK hydrodynamical equation of rotating radiation-driven winds for this latter solution, starting from standard values of the line force parameters (alpha, k, and delta), and then systematically varying the values of alpha and k. Terminal velocities and mass-loss rates that are in good agreement with those found in Be stars are obtained from the solutions with lower alpha and higher k values. Furthermore, the equatorial densities of such solutions are comparable to those that are typically assumed in ad hoc models. For very high values of k, we find that the wind solutions exhibit a new kind of behavior.