Stellar occultation of polarized light from circumstellar electrons. 4: Detached binary systems

The finite sizes of stars in detached binary systems are incorporated in the single scattering approximation of Brown, McLean, & Emslie (1978). In the absence of scatterer occultation, the predicted polarimetric variability is found to be represented by a terminating two harmonic time series, as previously found by Brown et al. (1978). When the occultation of scatterers by the light sources is included, additional Fourier harmonics are introduced. Model results are illustrated for a spherically symmetric scattering envelope centered on the primary star, in which it is found that for occultation effects to be identified in polarimetric data requires the separation of the system to be less than 10 times the radius of the primary, and for the primary to be the dominant light source.