Observations of forbidden Si II (35 microns) and Si I (25 microns) in Orion - Evidence of a wind shock near IRc2

Journal Article · Sat Jun 01 04:00:00 EDT 1991 · Astrophysical Journal; (United States)

DOI:https://doi.org/10.1086/170144· OSTI ID:5261380

Haas, M R; Hollenbach, D; Erickson, E F ^[1]

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1. NASA, Ames Research Center, Moffett Field, CA (USA)

Forbidden Si II and Si I line emission from Orion's BN-KL was measured using a cryogenic grating spectrometer aboard NASA's Kuiper Airborne Observatory. It is believed that the bulk of the forbidden Si II emission in Orion originates in photodissociated gas at the interface between the H II region and its parent molecular cloud. There is, however, a twofold enhancement in forbidden Si II emission near IRc2, which is attributed to fast dissociative J-shock where the wind from IRc2 impact slower moving material. Model fits suggest a silicon gas-phase depletion near ITc2 of 0.3-1.0 relative to solar. The spatial distribution of the forbidden Si II emission has a centralized peak. 74 refs.

• OSTI ID: 5261380
• Journal Information: Astrophysical Journal; (United States), Journal Name: Astrophysical Journal; (United States) Vol. 374; ISSN ASJOA; ISSN 0004-637X
• Country of Publication: United States
• Language: English

Related Subjects

640105* -- Astrophysics & Cosmology-- Galaxies
71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
COSMIC GASES
COSMIC RADIO SOURCES
DIFFRACTION GRATINGS
DISSOCIATION
DISTRIBUTION
ELEMENTS
EMISSION SPECTRA
ENERGY-LEVEL TRANSITIONS
FLUIDS
FORBIDDEN TRANSITIONS
GASES
GRATINGS
H2 REGIONS
INFRARED SPECTRA
INTERSTELLAR SPACE
NONMETALS
SEMIMETALS
SHOCK WAVES
SILICON
SPACE
SPATIAL DISTRIBUTION
SPECTRA
SULFUR