IS FS Tau B DRIVING AN ASYMMETRIC JET?
- Graduate Institute of Astrophysics, National Taiwan University, No. 1, Sec. 4, Roosevelt Road, Taipei 10617, Taiwan (China)
- Institute of Astronomy and Astrophysics, Academia Sinica (ASIAA), P.O. Box 23-131, Taipei 10641, Taiwan (China)
- Subaru Telescope, National Astronomical Observatory of Japan, 650 North A'ohoku Place, Hilo, HI 96720 (United States)
- Department of Physics and Astronomy, Stony Brook University, Stony Brook, NY 11794-3800 (United States)
- Department of Astronomy, School of Science, University of Tokyo, Tokyo 113-0033 (Japan)
FS Tau B is one of the few T Tauri stars that possess a jet and a counterjet as well as an optically visible cavity wall. We obtained images and spectra of its jet-cavity system in the near-infrared H and K bands using the Subaru/Infrared Camera and Spectrograph and detected the jet and the counterjet in the [Fe II] 1.644 {mu}m line for the first time. Within 2'' the blueshifted jet is brighter, whereas beyond {approx}5'' the redshifted counterjet dominates the [Fe II] emission. The innermost blueshifted knot is spectrally resolved to have a large line width of {approx}110 km s{sup -1}, while the innermost redshifted knot appears spectrally unresolved. The velocity ratio of the jet to the counterjet is {approx}1.34, which suggests that FS Tau B is driving an asymmetric jet, similar to those found in several T Tauri stars. Combining with optical observations in the literature, we showed that the blueshifted jet has a lower density and higher excitation than the redshifted counterjet. We suggest that the asymmetry in brightness and velocity is the manifestation of a bipolar outflow driving at different mass-loss rates, while maintaining balance of linear momentum. A full explanation of the asymmetry in the FS Tau B system awaits detail modeling and further investigation of the kinematic structure of the wind-associated cavity walls.
- OSTI ID:
- 22020465
- Journal Information:
- Astrophysical Journal, Vol. 749, Issue 1; Other Information: Country of input: International Atomic Energy Agency (IAEA); ISSN 0004-637X
- Country of Publication:
- United States
- Language:
- English
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