Mapping the Circumstellar Environment of T Tauri with Fluorescent H2Emission

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 H 2 and stellar chromospheric lines. Extended H 2 emission is seen up to 10'' from the T Tau system. The on-source and extended H 2 are both pumped by H I Lyα. The on-source H 2 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 H 2 is pumped locally and not by the stellar Lyα line. The H 2 to the north and west coincides with the evacuated cavity bounded by the optical reflection nebulosity; to the south the extended H 2 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.