SUBARCSECOND IMAGING AT 267 GHz OF A YOUNG BINARY SYSTEM: DETECTION OF A DUST DISK OF RADIUS LESS THAN 70 AU AROUND T TAURI N

The young binary system T Tauri was observed with the Owens Valley Millimeter Array in the 267 GHz continuum and HCO J 5 3–2 emission at 00.8 resolution, with the single-baseline interferometer of the James Clerk Maxwell Telescope–Caltech Submillimeter Observatory in the 357 GHz continuum and with the W. M. Keck Telescope at l 5 4 mm. The 267 GHz emission is unresolved, with a flux of mJy, located close 397 5 35 to the position of the optical star T Tau N. An upper limit of 100 mJy is obtained toward the infrared companion T Tau S. The 357 GHz continuum emission is unresolved, with a flux of Jy. HCO 5 3–2 was 1 1.35 5 0.68 J detected from a 20 diameter core surrounding T Tau N and S. Both stars are detected at 4 mm, but there is no evidence of the radio source T Tau R. We propose a model in which T Tau S is intrinsically similar to T Tau N but is obscured by the outer parts of T Tau N’s disk. A fit to the spectral energy distribution (SED) between 21 cm and 1.22 mm is constructed on this basis. Adopting an r surface density distribution and an exponentially truncated edge, disk masses of 21 and to M, are inferred for T Tau N and T Tau S, respectively. A 0.005–0.03 25 23 0.04 5 0.01 6 # 10 3 # 10 circumbinary envelope is also required to fit the millimeter to mid-infrared SED. M, Subject headings: binaries: close — ISM: molecules — stars: formation — stars: low-mass, brown dwarfs — stars: pre–main-sequence