Ultraviolet, optical and infrared observations of the Wolf-Rayet contact-eclipsing binary CQ Cephei

IUE spectra of CQ Cep covering virtually all binary phases are analyzed, together with new UBVJKL photometry and remeasurements of radial velocities from archived optical spectra. The high resolution UV interstellar line spectrum strongly supports CQ Cep's membership in the Cep OB1 association. Continuum light curves in 15 wavebands, from 0.13 to 3.6 microns, have been compared with predictions for a wide variety of new model calculations. Radial velocity curves are given for eight optical emission and absorption lines, and their disparity is discussed in terms of the likely extent of ionization zones and possible gas streams. None of the lines is a good indicator of the secondary's motion. Possible combinations of values of the binary separation and the stellar masses, radii, and temperatures are constrained by the light curve and radial velocity analyses, coupled with reasonable assumptions for a normal WN7 primary.