Optical and Infrared Studies of Jets and Winds from T Tauri Stars
Date Issued
2015
Date
2015
Author(s)
Liu, Chun-Fan
Abstract
Jets and winds emerging from young stars are ubiquitous during their formation. Among stars with different masses and ages, jets and winds from T Tauri Stars (stars of ∼ 0.08 to ∼ 2 solar masses with ages from ∼ 10^5 to ∼ 10^6 years) are the first known and most extensively studied because they are bright in line emission in the optical and near- infrared wavelengths. The T Tauri phase marks the first direct appearance of the star from which the surrounding envelope is dissipating, which enables direct observations toward the regions where the jets and winds are driven. Recent development of observational instruments has revolution- ized our understanding to T Tauri jets and outflows. With sub-arcsecond resolution observations obtained by the Hubble Space Telescope (HST) and large (> 8 m) ground-based telescopes aided with adaptive optics (AO), the structures of the jets and outflows are revealed down to a few tens of astronomical units (AU). High-dispersion spectrographs reach the velocity resolution of 10 to 50 km/s that resolves the line profiles and enables detailed kinematics studies of jets and winds. Detail information obtained from these observations confirms and at the same time shed light on solutions to some well-known puzzles in the research of T Tauri jets. In the thesis, the following aspects of T Tauri jets and winds are ad- dressed through spectroimaging studies: (1) asymmetries in velocities and physical conditions between the two sides of a bipolar outflow; (2) kinematic structure of the jets and winds; (3) ionization, excitation, and cooling of the jet; and (4) magnetic field structure of the region where field lines from the star, disk, and jet interact. Using archival spectroimaging data obtained from the HST and large ground-based telescopes, including the Subaru Telescope and the Very Large Telescope (VLT), aided with synthetic spectra calculated through the magnetocentrifugal X-wind models (e.g., Shang et al. 2002, 2010), these aspects are consistently viewed at a different angle.
Subjects
low-mass star formation
pre-main sequence
jets and outflows
magnetocentrifugal winds
X-rays
optical and infrared spectroscopy
Type
thesis
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