Abstract
We present the velocity structure of the 2.12 micron H2 emission in Orion, obtained with an IR Fabry-Perot interferometer with a spectral resolution of 24 km/s and a 2arcsec spatial resolution, covering a region of 3.6' by 3.6' (0.46 by 0.46 pc2) that contains the H2 filamentary finger system. A simple model is proposed to explain the observed low velocity structure as described by its radial moments: intensity, velocity centroid, velocity dispersion and skewness. We assume a strong wind of 230 km/s produced by IRc2 interacting with a set of molecular clumps with density of 5.6×105 cm-3. The scenario provides a good match to the observed moments is obtained, gives clues to the development of filaments or fingers and entrainment of the molecular material, and associates the observed high velocity blueshifted emission to the region. The H2 line emission is produced by a slow J-shock (20 km/s) in the clumps with an emissivity proportional to v1.8 . Estimates for the total wind mass and clumps mass yield 0.5 Msolar and 15 Msolar inside a radius of 1arcmin (0.1 pc). The individual clumps have masses and sizes of few × 10-3 Msolar and 0.007 pc, respectively. We conclude that the central 0.1 pc region surrounding the BN-KL nebula in front of OMC-1 is in the process of being disrupted by the strong wind of IRc2 on a time scale of 2000 yr.
