Bibcode
Laureijs, R. J.; Acosta-Pulido, J. a; Abraham, P.; Kinkel, U.; Klaas, U.; Castaneda, H. O.; Cornwall, L.; Gabriel, C.; Heinrichsen, I.; Lemke, D.; Pelz, G.; Schulz, B.; Walker, H. J.
Referencia bibliográfica
Astronomy and Astrophysics, v.315, p.L313-L316
Fecha de publicación:
11
1996
Revista
Número de citas
13
Número de citas referidas
11
Descripción
We observed the reflection nebula NGC 7023 at various positions using
wide and narrow band photometry centred on the 7.7 and 11.3μm PAH
emission features and wide band photometry at 20 and 25μm. No
significant variations have been detected over the nebula in the 7.3 and
20μm continuum relative to the total emission in the 6-15μm range
(hereafter {GAMMA}). This result supports the hypothesis that most of
the continuum emission in both bands come from very small grains. In
contrast, the 7.7 and 11.3μm PAH emission features show clear
variations. We find that in weaker radiation fields of the nebula the
11.3 and 7.7μm features are not the dominant emission components in
the 6-15μm range. The 11.5μm band increases whereas the 11.3μm
emission feature decreases relative to {GAMMA} in the outer parts of the
nebula. The effect can be explained by increased hydrogenation of PAH
molecules.