Radiation-driven winds in Of stars

The large number of subordinate lines of a representative ion are found to have a dominant effect on the force of radiation on material in O star atmospheres. The force is increased over that due to resonance lines alone so that rates of mass loss are obtained which are 100 times greater than previously thought possible. The force is related to the solution of the line-transfer problem, and it becomes a function of the local velocity gradient. A new stellar wind theory, with a different interpretation of the singular point, is developed to treat this situation. The rate of mass loss, and other properties of the model, are uniquely specified by the luminosity, mass, and radius of the star. Alternative static models do not exist. Numerical results give a rate of mass loss equal to .000006 solar mass per year for an O5 star, with a terminal velocity of 1500 km/sec. The rate of mass loss is sensitive to stellar parameters, while the terminal velocity is not.