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Identification of a strong emission line at 2.8935 mu in the spectrum of the Orion Nebula

L. B. Lucy
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Abstract

A strong emission line at 2.8935 mu discovered by Rubin et al. (2001) in an ISO SWS02 spectrum of the Orion Nebula is identified as the 4p - 4s multiplet of the O I triplets. Line formation is due to de-excitation cascades following UV-pumping of high triplet terms and occurs in the O I zone immediately behind the Hydrogen ionization front. This cascade mechanism also accounts for permitted O I triplet lines in the optical spectrum (Grandi 1975). An escape probability treatment of the O I cascades accounts for the strength of the 2.89 mu line and suggests interesting diagnostic possibilities for the optical lines.

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L. B. Lucy. 2001-10-05. Identification of a strong emission line at 2.8935 mu in the spectrum of the Orion Nebula. https://doi.org/10.1046/j.1365-8711.2002.05012.x

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