Polytropic models of radio stars.

Summary. This paper extends our previous work on models for radio emitting stars undergoing mass loss. The emission is assumed to be of thermal nature and the dynamics of the envelope is treated in the polytropic approximation. No limitations on the value of the polytropic index are introduced. Analytic results are derived whenever possible. For the other cases, the results of numerical integration of the model are fitted in a simple mathematical form that allows an easy application of the model to the observations. Detailed predictions, in particular for the mass-loss rate, are made for a few selected stars. A very good agreement is found with the estimates of the same quantities found by different authors. The possibility of reproducing the infrared spectrum is also discussed. Key words: radiostars stellar winds - mass loss