Resolving the forbidden-line emission regions of young stellar objects: DD Tauri

We present high spatial resolution, narrow-band images of the T Tauri star, DD Tau, obtained with the High-Resolution Camera of CFHT. We have resolved the forbidden line emission region (FLER) of this source, on a spatial scale 0″.55 in both [N II] and [S II]. The bulk of the continuum emission is concentrated in two knots that are separated by 0″.55 (77 AU) and oriented in the direction P.A. = 6°.4. The forbidden-line morphology is distinctly different from that of the continuum. The [N II] emission appears to be a "jetlike" extension connecting the two continuum knots. The [S II] emission seems to be confined to the northern knot. The southern knot (DD Tau B) is extended in the direction P.A. ≃ 130°. The orientation of the disk as defined by IR polarization measurements is P.A. ≃ 125°. We compare our observations with the existing theoretical models for the origin of FLERs.