Proper Motion Studies of Outflows from Classical T Tauri Stars

Abstract

In a previous paper (McGroarty & Ray 2004, 420, 975) we examined the environment of a number of evolved low-mass young stars, i.e. Classical T Tauri Stars, to see if they are capable of driving parsec-scale outflows. These stars - CW Tau, DG Tau, DO Tau, HV Tau C and RW Aur - were previously known to drive only "micro-jets" or small-scale outflows of < 1' or 0.04 pc at the distance of the Taurus-Auriga Cloud. We found that they drive outflows of 0.5pc - 1pc, based on the morphology and alignment of newly discovered and previously known HH objects with these sources and their "micro-jets". Here, we use a cross-correlation method to determine the proper motions of the HH objects in these five outflows (HH 220, HH 229, HH 702, HH 705 and HH 826 - HH 835) which in turn allows us to confirm their driving sources. Moreover, the tangential velocities of HH objects at large distances from their origin are currently poorly known so these proper motions will allow us to determine how velocities evolve with distance from their source. We find tangential velocities of typically 200 kms^-1 for the more distant objects in these outflows. Surprisingly, we find similar tangential velocities for the "micro-jets" that are currently being ejected from these sources. This leads us to suggest that either the outflow velocity was much higher 10^3 years ago when the more distant objects were ejected and that these objects have decelerated to their current velocity or that the outflow velocity at the source has remained approximately constant and the more distant objects have not undergone significant deceleration due to interactions with the ambient medium. Numerical simulations are needed before we can decide between these scenarios.

13 pages, 4 figures; accepted for publication in A&A. The resolution in the figures is very low, a high resolution version of this paper is available at http://physics.nuim.ie/staff/fmcgroarty.shtml

References in corpus (4)

• HST/STIS Spectroscopy of the Optical Outflow from DG Tau: Indications for Rotation in the Initial Jet Channel
• Non-axisymmetric accretion on the classical TTS RW Aur A
• Classical T Tauri stars as sources of parsec-scale optical outflows
• Parsec-Scale Herbig-Haro Outflows from Intermediate Mass Stars

Cited by in corpus (18)

• Molecular Outflows Identified in the FCRAO CO Survey of the Taurus Molecular Cloud
• Physical properties of the jet from DG Tauri on sub-arcsecond scales with HST/STIS
• Radio continuum emission from knots in the DG Tau jet
• Revealing the fastest component of the DG Tau outflow through X-rays
• Multi-epoch Sub-arcsecond [Fe II] Spectroimaging of the DG Tau Outflows with NIFS. I. First data epoch
• ESO-H$\alpha$~574 and Par-Lup3-4 Jets: Exploring the spectral, kinematical and physical properties
• Proper motions of collimated jets from intermediate-mass protostars in the Carina Nebula
• Multi-epoch Sub-arcsecond [Fe II] Spectroimaging of the DG Tau Outflows with NIFS. II. On the Nature of the Bipolar Outflow Asymmetry
• RW Aur A from the X-Wind Point of View: General Features
• Proper motions of molecular hydrogen outflows in the Rho Ophiuchi molecular cloud
• Kinematics of powerful jets from intermediate-mass protostars in the Carina nebula
• VLA Observations of DG Tau's Radio Jet: A highly collimated thermal outflow
• Sub-arcsecond high sensitivity measurements of the DG~Tau jet with e-MERLIN
• PDS 144: The First Confirmed Herbig Ae - Herbig Ae Wide Binary
• RW Aur B: a modest UX Ori type companion of the famous primary
• Variability of the SiO thermal line emission toward the young L1448-mm outflow
• Multifrequency study of HH 137 and HH 138: Discovering new knots and molecular outflows with Gemini and APEX
• Numerical simulations of stellar jets and comparison between synthetic and observed maps: clues to the launch mechanism