Mapping the Circumstellar Environment of T Tauri with Fluorescent H2 Emission

We have obtained three long-slit, far-UV spectra of the pre–main-sequence system T Tauri. These Hubble Space Telescope STIS spectra show a strong and variable on-source spectrum composed of both fluoresced H2 and stellar chromospheric lines. Extended H2 emission is seen up to 10″ from the T Tau system. The on-source and extended H2 are both pumped by H I Lyα. The on-source H2 is pumped by the red wing of a broad, self-absorbed Lyα line, while the progressions seen in the extended gas are pumped from near line center. This suggests that the extended H2 is pumped locally and not by the stellar Lyα line. The H2 to the north and west coincides with the evacuated cavity bounded by the optical reflection nebulosity; to the south the extended H2 coincides with the HH 255 outflow from the embedded infrared companion T Tau S. The spatial profile of the extended gas shows a prominent dip coincident with the position of T Tau S. This may be absorption by a disk associated with T Tau S. There is no evidence for absorption by a disk surrounding T Tau N large enough to obscure T Tau S.