Open AccessShocked H 2 and Fe + dynamics in the Orion bullets
Author(s) -
Tedds Jonathan A.,
Brand Peter W. J. L.,
Burton Michael G.
Publication year - 1999
Publication title -
monthly notices of the royal astronomical society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.058
H-Index - 383
eISSN - 1365-2966
pISSN - 0035-8711
DOI - 10.1046/j.1365-8711.1999.02604.x
Subject(s) - physics , astrophysics , bow shock (aerodynamics) , molecular cloud , shock (circulatory) , shock wave , stars , astronomy , mechanics , medicine
Observations of H 2 velocity profiles in the two most clearly defined Orion bullets are extremely difficult to reconcile with existing steady‐state shock models. We have observed [Fe II ] 1.644‐μm velocity profiles of selected bullets, and H 2 1–0 S(1) 2.122‐μm velocity profiles for a series of positions along and across the corresponding bow‐shaped shock fronts driven into the surrounding molecular cloud. Integrated [Fe II ] velocity profiles of the brightest bullets are consistent with theoretical bow shock predictions. However, observations of broad, singly peaked H 2 1–0 S(1) profiles at a range of positions within the most clearly resolved bullet wakes are not consistent with molecular shock modelling. A uniform, collisionally broadened background component which pervades the region in both tracers is inconsistent with fluorescence arising from the ionizing radiation of the Trapezium stars alone.