Destruction of the Environment of the BN‐KL Nebula

We describe observations of the 2.12 μm molecular hydrogen emission in Orion using an IR Fabry-Perot interferometer with a spectral resolution of 24 km s -1 and a 2'' spatial resolution covering a region of 3 6 × 3 6 (0.46 × 0.46 pc 2 ) that contains the H 2 filamentary finger system located to the northwest of the Trapezium. We develop a simple model 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 -1 produced by IRc2 interacting with a set of molecular clumps with density of 5.6 × 10 5 cm -3 . This simple model provides a good match to the observed moments, 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 driving source of the wind requires a high mass-loss rate and thus is likely IRc2. The H 2 line emission is produced by a slow J-type shock (20 km s -1 ) in the clumps with an emissivity proportional to v 1.8 . Estimates for the total wind mass and clump mass yield 0.5 and 15 M ☉ inside a radius of 1' (0.1 pc). The individual clumps have masses and sizes of few × 10 −3 M ☉ 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 timescale of 2000 yr.