Emission features in the 4-13 micron spectra of the reflection nebulae NGC 7023 and NGC 2023
K. Sellgren, L. J. Allamandola, J. D. Bregman, M. W. Werner, D. H. Wooden;
ApJ, 1985, 299, 416
ABSTRACT:Spectroscopy from 4 to 13 microns of the visual reflection nebulae NGC 7023 and NGC 2023 has been obtained.
These data, together with previous
work from 1 to 4 microns, show that the spectra of these sources consist of a
relatively flat continuum from 1 to 13 microns and six emission features at 3.3,
3.4, 6.2, 7.7, 8.6, and 11.3 microns.
The observations rule out
equilibrium thermal emission for the features and continuum in reflection
nebulae, and point toward a nonequilibrium emission mechanism such as thermal
emission from thermally fluctuating small grains or fluorescence from large
molecules.
The similarity of the emission feature spectra in reflection nebulae to
those in other sources suggests a universal emission mechanism, thus
implying nonequilibrium emission mechanisms in other sources.
KEYWORDS: emission spectra, infrared spectra, reflection nebulae, stellar spectrophotometry, fluorescence, grain size, molecules, near infrared radiation, thermal emission
CODE: sellgren85