NOAO > Observing Info > Approved Programs > 2010B-0390
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NOAO > Observing Info > Approved Programs > 2010B-0390 |
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PI: Patrick Hartigan, Rice University, hartigan@sparky.rice.edu
Address: Physics Department, 6100 S. Main, Houston, TX 77005, USA
Title: Dynamics Within the Collimation Region of the HH 444 Stellar Jet
Abstract:
How accretion disks drive supersonic jets is one of the major
unsolved problems in astrophysics. Stellar jets are ideal subjects for
studying this phenomenon because they radiate optically thin forbidden
emission lines that are resolved both spatially and spectrally, and
these jets have measurable proper motions within a few years. When
enough emission lines are observed with good S/N, new analysis
techniques that make use of the strong charge exchange coupling between
hydrogen, oxygen, and nitrogen make it possible to determine the
ionization fractions, densities, and temperatures in jets as a function
of both position and radial velocity everywhere the jet radiates.
Probing physical conditions in jets throughout phase space in this
manner is an extremely powerful technique, but it has not been brought
to bear on this problem because the few existing observations with
enough sensitvity and resolution lack the wavelength coverage needed for
a complete analysis. This proposal seeks to remedy this deficit by
obtaining a deep position-velocity diagram that will measure all the
important optical transitions within HH 444, a jet previously observed
with HIRES but over a limited spectral range. The proposed observations
will provide the missing dynamical information needed to diagnose
entrainment, shock heating, and possibly even reconnection in the
critical zone where jets emerge from disks. In addition, enough time
has now passed since the previous observations to allow us to track
proper motions, and thereby learn which features in the position-
velocity map of the jet evolve dynamically, and which are static.
National Optical Astronomy Observatory, 950 North Cherry Avenue, P.O. Box 26732, Tucson, Arizona 85726, Phone: (520) 318-8000, Fax: (520) 318-8360
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NOAO > Observing Info > Approved Programs > 2010B-0390 |
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