Time-Variable Jet Ejections from RW Aur A, RY Tau and DG Tau

Abstract

We present Gemini-NIFS, VLT-SINFONI and Keck-OSIRIS observations of near-infrared [Fe II] emission associated with the well-studied jets from three active T Tauri stars; RW Aur A, RY Tau and DG Tau taken from 2012-2021. We primarily covered the redshifted jet from RW Aur A, and the blueshifted jets from RY Tau and DG Tau, to investigate long-term time variabilities potentially related to the activities of mass accretion and/or the stellar magnetic fields. All of these jets consist of several moving knots with tangential velocities of 70-240 km s-1, ejected from the star with different velocities and at irregular time intervals. Via comparison with literature, we identify significant differences in tangential velocities for the DG Tau jet between 1985-2008 and 2008-2021. The sizes of the individual knots appear to increase with time, and in turn, their peak brightnesses in the 1.644-micron emission decreased up to a factor of ~30 during the epochs of our observations. A variety of the decay timescales measured in the [Fe II] 1.644 micron emission can be attributed to different pre-shock conditions if the moving knots are unresolved shocks. However, our data do not exclude the possibility that these knots are due to non-uniform density/temperature distributions with another heating mechanism, or in some cases due to stationary shocks without proper motions. Spatially resolved observations of these knots with significantly higher angular resolutions are necessary to better understand their physical nature.

24 pages, 11 figures, 8 tables, accepted for ApJS

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Cited by in corpus (4)

• Ejection Patterns in the DG Tau Jet Over the Last 40 Years: Insights into Mass Accretion Variability
• The accretion-ejection connection in the asymmetric Th 28 jet revealed by MUSE-NFM
• The MATISSE view of the inner region of the RY Tau protoplanetary disk
• Variability of the DG Tau Forbidden Emission Line Low Velocity Component