THE WOLF-RAYET BINARY V444 CYGNI UNDER THE SPECTROSCOPIC MICROSCOPE .1. IMPROVED CHARACTERISTICS OF THE COMPONENTS AND THEIR INTERACTION SEEN IN HE

A large accumulation of high signal-to-noise, moderate-resolution opti cal spectra has led to an unprecedented analysis of the radial velocit ies of emission and absorption lines in the close binary system V444 C yg (WN 5 + O6 III-V). Improved orbital elements and masses are K(WR) = 332.6 +/- 3.0 km s-1, K, = 108.4 + 4.7 km s-1, a sin i = 35.8 +/- 0.4 R., e = 0.036 +/- 0.009, M(WR) sin3 i = 8.8 +/-0.4 M., M(o) sin3 i = 26.3 +/- 1.0 M.. With i = 78.7-degrees +/- 0.5-degrees from previous s tudies, these yield a = 38.0 +/- 0.5 R., M(WR) = 9.3 +/- 0.5 M., M(o) = 27.9 +/- 1.1 M.. Other results include (1) the stable presence of sh ort-period pulsations, P congruent-to 0.36d in the O-C deviations from the W-R orbital curve based on the He II 4686 and 5412 radial velocit ies; (2) supersynchronous rotation of the O star by a factor approxima tely 2: v(e) sin i = 215 +/- 13 km s-1; (3) sensitivity, especially of the He I 4471, 4922, and 5876 lines, to the presence of a wind-wind c ollision region in the form of a bow shock around the O star.