A spectroscopic search for colliding stellar winds in O-type close binary systems. III - 29 UW Canis Majoris

• Published in: The Astrophysical journal Vol. 407; no. 1; pp. 252 - 265
• Main Authors: Wiggs, Michael S., Gies, Douglas R.
• Format: Journal Article
• Language: English
• Published: Legacy CDMS University of Chicago Press 10.04.1993
• Subjects: Astronomy; Astrophysics; Binary and multiple stars; Earth, ocean, space; Exact sciences and technology; Spectroscopic binaries. Close binaries; Stars; Stellar winds; Line intensity; Early type stars; O stars; Emission spectra; Ultraviolet spectra; Visible spectra; Close binary stars; Mass loss; P Cygni line profile; Main sequence stars; Orbits
• ISSN: 0004-637X; 1538-4357
• DOI: 10.1086/172510

The orbital-phase variations in the optical emission lines and UV P Cygni lines of the massive O-type binary 29 UW Canis Majoris are investigated in a search for evidence of colliding winds. High SNR spectra of the H-alpha and He I 6678-A emission lines are presented, and radial velocity curves for several features associated with the photosphere of the more luminous primary star are given. The H-alpha features consists of a P Cygni component that shares the motion of the primary, and which probably originates at the base of its wind, and a broad, stationary emission component. It is proposed that the broad emission forms in a plane midway between the stars where the winds collide. A simple geometric model is used to show that this placement of the broad component can explain the lack of orbital velocity shifts, the near-constancy of the emission strength throughout the orbit, the large velocities associated with the H-alpha wings, and the constancy of the velocity range observed.