Rates of energy gain and loss in the circumstellar envelopes of Be stars: The disk model

We have investigated the kinetic temperatures assumed by Waters, Cote, st L amers for the circumstellar envelopes of a group of Be stars. Waters introd uced a simple equatorial disk model with rho(r) proportional to r(-n) to de scribe the physical characteristics of Be star disks. Since this equatorial disk model was applied to a large number of stars, it is important to ensu re that the kinetic temperatures assumed by Waters et al. were reasonable. We have investigated their choice of kinetic temperature in two ways. Initi ally we tested the appropriateness of the temperatures assumed by evaluatin g the rates of energy gain and loss. Then, based on equating the rates of e nergy gain and loss, we self-consistently determined the temperature struct ure for these envelopes. Our investigation included the stars gamma Gas, de lta Cen, psi Per, and beta CMi. For each of the stars examined we discovere d that the constant temperature of the envelope assumed by Waters et al. wa s too high by a factor of 2-3.