WINDS FROM ACCRETION DISKS - ULTRAVIOLET LINE FORMATION IN CATACLYSMIC VARIABLES

Winds from accretion disks in cataclysmic variable stars are ubiquitou s. Observations by IUE reveal P Cygni-shaped profiles of high-ionizati on lines which are attributed to these winds. We have studied the form ation of UV emission lines in cataclysmic variables by constructing ki nematical models of biconical rotating outflows from disks around whit e dwarfs. The photoionization in the wind is calculated taking into ac count the radiation fields of the disk, the boundary layer, and the wh ite dwarf. The three-dimensional radiative transfer is solved in the S obolev approximation. Effects on the line shapes of varying basic phys ical parameters of the wind, such as accretion and mass-loss rates, te mperature of the boundary layer, rotation, as well as inclination angl e, are shown explicitly. We identify and map the resonant scattering r egions in the wind which have strongly biconical character regardless of the asumed velocity and radiation fields. Rotation at the base of t he wind introduces a radial shear which decreases the line optical dep th and reduces the line core intensity. We find that it is possible to reproduce the observed P Cygni line shapes and make some predictions to be verified in high-resolution observations.