ALMA OBSERVATIONS OF THE T TAURI BINARY SYSTEM AS 205: EVIDENCE FOR MOLECULAR WINDS AND/OR BINARY INTERACTIONS

In this study, we present high-resolution millimeter observations of the dust and gas disk of the T Tauri star AS 205N and its companion, AS 205 S, obtained with the Atacama Large Millimeter Array. The gas disk around AS 205 N, for which infrared emission spectroscopy demonstrates significant deviations from Keplerian motion that has been interpreted as evidence for a disk wind, also displays significant deviations from Keplerian disk emission in the observations presented here. Detections near both AS 205 N and S are obtained in 1.3 mm continuum, (CO)-C-12 2-1, (CO)-C-13 2-1, and (CO)-O-18 2-1. The 12CO emission is extended up to similar to 2 '' from AS 205 N, and both (CO)-C-12 and (CO)-C-13 display deviations from Keplerian rotation at all angular scales. Two possible explanations for these observations hold up best to close scrutiny-tidal interaction with AS 205 S or disk winds (or a combination of the two)-and we discuss these possibilities in some detail.