In this Letter , we present a series of seven observations of the compact , non-thermal radio source associated with T Tauri South made with the Very Long Baseline Array over the course of one year .
The emission is found to be composed of a compact structure most certainly originating from the magnetosphere of an underlying pre-main sequence star , and a low-brightness extension which may result from reconnection flares at the star-disk interface .
The accuracy of the absolute astrometry offered by the VLBA allows very precise determinations of the trigonometric parallax and proper motion of T Tau South .
The proper motion derived from our VLBA observations agrees with that measured with the VLA over a similar period to better than 2 mas yr ^ { -1 } , and is fully consistent with the infrared proper motion of T Tau Sb , the pre-main sequence M star with which the radio source has traditionally been associated .
The parallax , \pi = 7.07 \pm 0.14 mas , corresponds to a distance of 141.5 ^ { +2.8 } _ { -2.7 } pc .