The 3. 3 micron feature, H2, and ionized gas in the Orion bar

Journal Article · Mon Jan 01 04:00:00 EST 1990 · Astrophysical Journal; (USA)

DOI:https://doi.org/10.1086/168299· OSTI ID:6904619

Sellgren, K; Tokunaga, A T; Nakada, Y ^[1]

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1. Hawaii Univ., Honolulu (USA) Tokyo Univ. (Japan)

The results of spectroscopy of the 3.3 micron feature, H2 emission, P-alpha, and Br-alpha, obtained along a line perpendicular to the Orion ionization front, are presented. The intensity of the 3.3 micron feature reaches a maximum between the ionization front and the H2 peak. The 3.33 micron spatial distribution appears to be due to destruction of the emitting material within the H II region and extinction of the exciting radiation between the edge of the H II region and the H2 peak, resulting in a maximum between the ionization front and the H2 peak. The H2 peak is consistent with either being due to a shock front or being due to UV-pumped fluorescence from dense clumps of H2. The width of the 3.3 micron feature observed at high spectral resolution is constant in regions of varying UV flux. It is suggested that the strength of the UV field is not the cause of the variations in the 3.3 micron feature width observed in other sources, but rather that these variations are caused by a compositional change related to the age of the emitting material. 29 refs.

• OSTI ID: 6904619
• Journal Information: Astrophysical Journal; (USA), Journal Name: Astrophysical Journal; (USA) Vol. 349; 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 RADIO SOURCES
DISTRIBUTION
ELECTROMAGNETIC RADIATION
EMISSION SPECTRA
FLUIDS
GASES
H2 REGIONS
INFRARED SPECTRA
INTERSTELLAR SPACE
IONIZATION
IONIZED GASES
NEBULAE
RADIATIONS
SHOCK WAVES
SPACE
SPATIAL DISTRIBUTION
SPECTRA
SPECTROSCOPY
ULTRAVIOLET RADIATION
VARIATIONS