Doppler tomography of the stellar wind of the Wolf-Rayet binary star V444 Cygni
High dispersion IUE observations of V444 Cyg around its orbit, emphasizing the C IV, N V, N IV, and He II profile variations are presented. The density and velocity structure of the wind, and details of the interaction between the O star and WR wind are discussed. Absorption becomes strongest and most nearly symmetric during primary eclipse, when the line of sight passes through the densest and most sluggish part of the wind. As the orbit progresses through quadrature, the terminal velocity does not change substantially, although the line of sight to the O star intersects more distant portions of the wind at lower velocity, indicating that there is still a considerable absorption in the line being seen toward the WR core. At secondary minimum, the core is partially occulted and the presence of the cavity eliminates the absorption component, while at third quadrature, a profile almost identical in appearance to that at first quadrature is observed.