IUE spectroscopy of hot binary stars HD 108,HD 149404 and HD 163181.

Abstract

High-dispersion IUE UV spectra of the hot binaries HD 108, HD 149404 and HD 163181 obtained at several orbital phases is presented in an attempt to assess the influence of the companion on stellar wind outflow. Spectra of HD 108, which has an extreme Of spectrum in the visible, show velocity changes over a range of 40 km/sec in the weak absorption lines, which, however, do not correlate with changes in the wind lines and do not support the binary nature of the object. The double-line O-type spectroscopic binary HD 149404 exhibits a stellar wind in the UV resonance lines which is not phase dependent. HD 163181 shows a clear phase dependence in its stellar wind, with wind phenomena strongest near periastron passage at phase 0.35 in the photometric ephemeris. An expanding Fe shell is indicated in all spectra, with expansion velocities lower than the main wind lines.