Illumination in Symbiotic Binary Stars: Non‐LTE Photoionization Models. II. Wind Case

We describe a non-LTE photoionization code to calculate the wind structureand emergent spectrum of a red giant wind illuminated by the hot component of asymbiotic binary system. We consider spherically symmetric winds with severaldifferent velocity and temperature laws and derive predicted line fluxes as afunction of the red giant mass loss rate, \mdot. Our models generally matchobservations of the symbiotic stars EG And and AG Peg for \mdot about 10^{-8}\msunyr to 10^{-7} \msunyr. The optically thick cross- section of the red giantwind as viewed from the hot component is a crucial parameter in these models.Winds with cross-sections of 2--3 red giant radii reproduce the observedfluxes, because the wind density is then high, about 10^9 cm^{-3}. Our modelsfavor winds with acceleration regions that either lie far from the red giantphotosphere or extend for 2--3 red giant radii.Comment: 51 pages, LaTeX including three tables, requires 15 Encapsulated Postscript figures, to appear in Ap