USING OPTICAL/NEAR-INFRARED INTERFEROMETRIC POLARIMETRY TO PLACE CONSTRAINTS ON THE DISKS SURROUNDING Be STARS

Abstract

We present predictions for the normalized Stokes visibilities of a Be star disk, as would be measured by an interferometric polarimeter. Using both a simple geometric model for the disk as well as a more complex radiative transfer model, we investigate, in detail, the effect of each of the model parameters on the resultant normalized Stokes visibilities. We find normalized visibility amplitudes for the total star and disk system of ~10–2-10–3 at shorter baselines, and ~10–3-10–4 at longer baselines, requiring, at small and moderate baselines, an accuracy for interferometric polarization observations better than ~10–3-10–4, including all random and systematic errors. Provided this level of accuracy is attainable, we find that the Stokes Q visibility may be important both for the removal of model degeneracies present when considering the intensity alone, as well as for providing an estimate of the inclination angle of the disk.