The excitation within the molecular hydrogen jets of the protostellar outflow HH 212

Smith, M.D. and O'Connell, B. and Davis, C.J. (2007) The excitation within the molecular hydrogen jets of the protostellar outflow HH 212. Astronomy and Astrophysics, 466 (2). 565-U19. ISSN 0004-6361. (The full text of this publication is not available from this repository)

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Abstract

The near-infrared twin jets emanating from the HH 212-mm protostar are remarkable for their symmetry. By performing integral field spectroscopy with the UIST imager-spectrometer on UKIRT, we investigate the chains of bright knots and arcs within the jets to gain insight into the underlying physics and dynamics. We obtain numerous images associated with line emission from vibrationally-excited molecular hydrogen and the [FeII] line at 1.64 mu m. This allows us to study the spatial variation in excitation of the inner knots and outer bow- shaped objects. We find that the excitation properties are consistent with outward-moving bow shocks close to the plane of the sky. However, there is a gradient in excitation transverse to the jet axis across the inner knots on the scale of 0.1 arcsec. This C-shaped inner symmetry suggests a transverse source motion rather than precession, possibly related to the jet bending and the transverse gradient in radial velocity. Moreover, the bow models predict that the iron emission should peak further ahead of the molecular emission than actually observed. This leads us to propose that each inner knot consists of two closely-spaced asymmetric bows, as found for the outer bows which clearly occur in distinct pairs, well-separated in a lower density environment. The weak inter-knot emission may then be generated within oblique shock waves resulting from the deflection of fluid across asymmetric bow flanks.

Item Type: Article
Uncontrolled keywords: ISM : jets and outflows; circumstellar matter; infrared : ISM; Herbig-Haro objects; stars : formation
Subjects: Q Science > QB Astronomy
Divisions: Faculties > Science Technology and Medical Studies > School of Physical Sciences > Centre for Astrophysics and Planetary Sciences
Faculties > Science Technology and Medical Studies > School of Physical Sciences
Depositing User: Suzanne Duffy
Date Deposited: 19 Mar 2008 08:35
Last Modified: 14 Jan 2010 14:06
Resource URI: http://kar.kent.ac.uk/id/eprint/2309 (The current URI for this page, for reference purposes)
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