Mapping WR140 from infrared spectroscopy and imaging

Abstract

Observations of the 1.083-micron He I line in WR140 (HD 193793) show P-Cygni profiles which varied as the binary system went through periastron passage. A sub-peak appeared on the normally flat-topped emission component and then moved across the profile consistent with its formation in the wind-collision region. Variation of the absorption component provided constraints on the opening angle (theta) of the wind-collision region. Infrared (2-10 micron) images observed with a variety of instruments in 2001-04 resolve the dust cloud formed in 2001, and show it to be expanding at a constant rate. Owing to the high eccentricity of the binary orbit, the dust is spread around the orbital plane in a 'splash' and we compare the dust images with the orientation of the orbit.