EDP Sciences
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Volume 377, Number 1, October I 2001
Page(s) 285 - 296
Section Diffuse matter in space
DOI http://dx.doi.org/10.1051/0004-6361:20011110

A&A 377, 285-296 (2001)
DOI: 10.1051/0004-6361:20011110

Echelle spectroscopy of H $\mathsf{_2}$ in the HH 111 jet

C. J. Davis1, K. W. Hodapp2 and L. Desroches1, 3

1  Joint Astronomy Centre, 660 North A'ohoku Place, University Park, Hilo, Hawaii 96720, USA
2  Institute for Astronomy, 640 North A'ohoku Place, Hilo, Hawaii 96720, USA
    e-mail: hodapp@ifa.hawaii.edu
3  Dept. of Physics, University of Victoria, PO Box 3055 STN CSC, Victoria, BC V8W 3P6, Canada

(Received 22 June 2001 / Accepted 3 August 2001 )

Near-Infrared echelle spectra of the Herbig-Haro knots F-P in the western lobe of the HH 111 outflow are presented. 10 adjacent, parallel slit positions were observed so that the kinematics could be mapped across the width of the flow. We find broad (FWZI $\sim
100$ km s-1), two-component H2 profiles in the knots nearest the source; the profiles converge to a single, intermediate-velocity peak ( $V_{\rm LSR} \sim 50$ km s-1) at knot P. The kinematic signature of the HH 111 jet in H2 is very similar to that seen at optical wavelengths (from both radial and tangential velocity meaurements). In conjunction with published proper-motion (knot/shock pattern speed) measurements, we interpret the data in terms of a simple geometrical bow shock model. The model infers a high pre-shock velocity, of the order of 200-250 km s-1, with H2 excitation in the extended bow wings in knots L, H and F, though exclusively near the bow head in knot P, with probably C-type shock excitation throughout.

Key words: interstellar medium: jets and outflows -- stars: pre-main-sequence -- observations -- Herbig-Haro objects: HH 111

Offprint request: C. J. Davis, c.davis@jach.hawaii.edu

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