The Discovery of a New Infrared Emission Feature at 1905 Wavenumbers (5.25 Microns) in the Spectrum of BD +30 degrees 3639 and Its Relation to the Polycyclic Aromatic Hydrocarbon Model
Abstract
A new IR emission feature at 1905/cm (5.25 microns) has been discovered in the spectrum of BD + 30 deg 3639. This feature joins the family of well-known IR emission features at 3040, 2940, 1750, 1610, '1310', 1160, and 890/cm. The origin of this new feature is discussed and it is assigned to an overtone or combination band involving C-H bending modes of polycyclic aromatic hydrocarbons (PAHs). Laboratory work suggests that spectral studies of the 2000-1650/cm region may be very useful in elucidating the molecular structure of interstellar PAHs. The new feature, in conjunction with other recently discovered spectral structures, suggests that the narrow IR emission features originate in PAH molecules rather than large carbon grains.
- Publication:
-
The Astrophysical Journal
- Pub Date:
- October 1989
- DOI:
- 10.1086/185552
- Bibcode:
- 1989ApJ...345L..59A
- Keywords:
-
- Astronomical Spectroscopy;
- Emission Spectra;
- Hydrocarbons;
- Infrared Sources (Astronomy);
- Interstellar Gas;
- Line Spectra;
- Molecular Gases;
- Spectral Bands;
- Astrophysics;
- INFRARED: SPECTRA;
- INTERSTELLAR: GRAINS;
- INTERSTELLAR: MOLECULES