Mass Loss in a B2 IIIe Star: omega Orionis 1978--1984

Abstract

Combination of long-term optical polarimetric, photometric, spectrometric, and ultraviolet spectral data have confirmed that all observed portions of ω Ori's outer atmosphere are variable on a variety of time scales. The spectacular polarization episodes are correlated with the presence of continuum flux and color changes but are not correlated with the strength of the highly ionized stellar wind or with episodes of enhanced wind variability. A straightforward interpretation of the available data is that the continuum polarization, continuum-magnitude changes, and color changes are produced in a presumably equatorial disk close to the stellar photosphere. The highly ionized stellar wind, which is expected to be produced relatively close to the star, is apparently spatially separated from the disk, probably at high latitudes, although different radii cannot be ruled out.