The dependence of polarization on orbital phase and beat phase at 9 GHz. Visibility data were folded on the beat period, and each bin of 0.1 in beat phase separately imaged in IQUV . Beat phase zero is defined as in Fig. 9. This procedure was repeated for two subsets at orbital phases ≈ 0 and 1. An identically zero polarization indicates that imfit was unable to identify a source at the location of AR Sco in that Stokes parameter.