Scattered light signatures of magnetic accretion in classical T Tauri stars

The magnetic accretion model as applied to T Tauri stars predicts the formation of hot spots or rings on the stellar surface where accreting disk material impacts the stellar surface at or near the magnetic poles. When the magnetic poles are not aligned with the stellar rotation axis, or the hot spots are nonuniform, brightness variations arise as the hot spots rotate into and out of view. We have investigated the effects on the scattered light images of a T Tauri star-plus-disk system of nonaxisymmetric illumination of the circumstellar disk by hot starspots. We find that changes in the scattered light pattern occur during a stellar rotation period. These changes are observable with current high-resolution imagery and provide a further observational test of the magnetic accretion theory. The observed brightening and dimming of HH 30's scattered light disk may be explained by such a model, although further synoptic observations are required to confirm this.