CROSS-CORRELATION CHARACTERISTICS OF OB STARS FROM IUE SPECTROSCOPY

We present a catalogue of homogeneous measures of the linewidth parame ter, v(e) sin i, for 373 O-type stars and early B supergiants (includi ng the separate components of 25 binary and three triple systems), pro duced by cross-correlating high-resolution, short-wavelength IUE spect ra against a 'template' spectrum of tau Sco. We also tabulate terminal velocities. There are no O supergiants in our sample with v(e) sin i < 65 km s(-1), and only one supergiant earlier than B5 has v(e) sin i < 50 km s(-1), confirming that an important line broadening mechanism in addition to rotation must be present in these objects. A calibratio n of the area under the cross-correlation peak against spectral type i s used to obtain estimates of continuum intensity ratios of the compon ents in 28 spectroscopically binary or multiple systems. At least seve n SB2 systems show evidence for the 'Struve-Sahade effect', a systemat ic variation in relative line strength as a function of orbital phase. The stellar wind profiles of the most rapid rotator in our sample, th e O9 III:n star HD 191423 (v(e) sin i = 436 km s(-1)), show it to hav e a 'wind-compressed disc' similar to that of HD 93521; this star and other rapid rotators are good candidates for studies of non-radial pul sation.