Adaptive Optics Spectroscopy of the [Feii] Outflows from HL Tauri and RW Aurigae

Abstract

We present new results of [Fe II] λ1.644 μm spectroscopy toward the jets from HL Tau and RW Aur carried out with the Subaru Telescope combined with the adaptive optics system. We observed the regions within 2''-3'' from the stars with the subarcsecond resolutions of 05 and 02 for HL Tau and RW Aur, respectively. In addition to the strong high-velocity component (HVC) extended along each jet, we detected a blueshifted low-velocity component (LVC) seen as a wing or shoulder of the HVC at each stellar position. The position velocity diagrams of the two objects show a characteristic similar to those of the cold disk wind and X-wind models in that the [Fe II] line width is broad close to the stellar position and narrower at the extended jet. A closer comparison suggests, however, that the disk wind model tends to have too large a line width at the HVC, while the X-wind model has excess redshifted emission at the stellar position. The narrow velocity width with symmetric line profiles of the observed HVC supports an X-wind-type model, while the LVC, located away from the star, favors the presence of a disk wind. The [Fe II] emission shows a gap of 08 for HL Tau and a marked drop of Y ~ -02 for RW Aur between the redshifted jet and the star, which indicate optically thick disks of ~160 and <40 AU in radius, respectively. Part of the Br12 emission of HL Tau originates from the jet itself because its normalized line profile shows a signigicantly large deviation from the normalized continuum in spatial profile.