The Spatial Distribution of Fluorescent H₂ Emission near T Tauri

Abstract

New subarcsecond far-UV observations of T Tau with Hubble Space Telescope STIS show spatially resolved structures in the 2^''×2^'' area around the star. The structures are apparent in multiline emission of fluorescent H₂ pumped by Lyα. One emission structure follows the cavity walls observed around T Tau N in scattered light in the optical. A temperature of >=1000 K is required to have a high enough population in the H₂ to produce the observed fluorescent lines; in the cool environment of the T Tau system, shock heating is required to achieve this temperature at distances of a few tens of AU. Fluorescent H₂ along the cavity wall represents the best evidence to date for the action of low-density, wide opening angle outflows driving cavities into the molecular medium at scales <=100 AU. A southern region of emission consists of two arcs, with shape and orientation similar to the arcs of H₂ 2.12 μm and forbidden-line emission crossing the outflow associated with the embedded system T Tau S. This region is located near the centroid of forbidden-line emission at the blueshifted lobe of the north-south outflow.