Optical [Ne III] Jet from DG Tau with VLT/X-Shooter Spectra
Chun-Fan Liu1,2,3*, Hsien Shang1,3, Gregory J. Herczeg4, Frederick M. Walter5
1Institute of Astronomy and Astrophysics, Academia Sinica, Taipei, Taiwan
2Graduate Institute of Astrophysics, National Taiwan University, Taipei, Taiwan
3Theoretical Institute for Advanced Research in Astrophysics, Academia Sinica, Taipei, Taiwan
4Kavli Institute for Astronomy and Astrophysics, Peking University, Beijing, China
5Department of Physics and Astronomy, Stony Brook University, Stony Brook, New York, United States of America
* presenting author:Chun-Fan Liu, email:cfliu@asiaa.sinica.edu.tw
We present optical long-slit spectra of the blueshifted jet of DG Tau obtained with the Very Large Telescope (VLT) X-Shooter spectrograph. DG Tau is a flat-spectrum T Tauri star driving a bright jet that emits from X-ray to radio wavelengths. The doubly ionized neon forbidden line [Ne III] λ3869 was discovered in the inner 3" microjet and 2 outer knots located at 7" and 13" from the star, respectively. The existence of doubly ionized neon along the jet suggests high ionization maintained in the jet, which may be attributed to the frozen-in ionization of hard X-ray irradiation from star-disk interaction near the launching region and shock ionization in the jet. Comparing with other optical line emission and extended soft X-ray emission along the jet axis, we aim at investigating the outflow history of DG Tau.

Keywords: low-mass star formation, jets and outflows, pre-main-sequence stars, individual (DG Tau)