SUBMILLIMETER CO OBSERVATIONS OF WARM GAS AROUND T-TAURI STARS

We report the first observations of T Tauri stars (T-, HL-, DG-, RY-, and GG-Tau) in the (CO)-C-12 (6-5) line. The observations trace the dynamics of warm (T greater-than-or-equal-to 60 K) and dense (greater-than-or-equal-to 10(5) cm-3) gas on a scale below 10''. The CO submillimeter emission probably originates in shocks where a stellar wind interacts with a high column density of molecular material close to the star. Additional (CO)-C-12 (3-2) and (CO)-O-18 (2-1) data show that the spatial distributions and line widths in T-Tau and HL-Tau are not consistent with Keplerian rotation or residual infall but can be explained by warm, dense, slowly outflowing material. We also conclude that the dust associated with the warm molecular outflow could account for a substantial fraction of T-Tau's far-infrared continuum emission.