A SPECTROSCOPIC SEARCH FOR COLLIDING STELLAR WINDS IN O-TYPE CLOSE BINARY SYSTEMS. V. HD 149404

We present new Ha emission-line spectra and an analysis of the mass out—ow for the massive close binary HD 149404. Spectra obtained between 1995 and 1997 show evidence of coherent orbital phase¨ related variations superimposed on both long-term and short-term emission strength variations. We use a Doppler tomography algorithm to construct velocity maps of the emission intensity, and these demonstrate that emission displays two broad peaks that follow sinusoidal radial velocity curves that are signi—cantly diUerent from the orbital velocity curves of either star. We present a model for the kinematics and distribution of the emitting circumstellar gas, and we argue that most of the emission comes from ) )