Open AccessIdentification of a strong emission line at 2.8935 μm in the spectrum of the Orion Nebula
Author(s) -
Lucy L.B.
Publication year - 2002
Publication title -
monthly notices of the royal astronomical society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.058
H-Index - 383
eISSN - 1365-2966
pISSN - 0035-8711
DOI - 10.1046/j.1365-8711.2002.05012.x
Subject(s) - physics , orion nebula , nebula , multiplet , emission spectrum , line (geometry) , astrophysics , spectral line , ionization , emission nebula , cascade , spectrum (functional analysis) , atomic physics , ion , stars , astronomy , chemistry , geometry , mathematics , chromatography , quantum mechanics
A strong emission line at 2.8935 μm discovered by Rubin et al. in an ISO SWS02 spectrum of the Orion Nebula is identified as the multiplet of O i . Line formation is due to de‐excitation cascades following UV‐pumping of high 3 S o and 3 D o 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 of the Nebula, as shown by Grandi. An escape probability treatment of the O i cascades accounts for the strength of the λ 2.89‐μm line and suggests interesting diagnostic possibilities for the optical lines.