High-Resolution Spectroscopy of the C 2 Swan 0--0 Band from Comet P/Halley
Abstract
High-resolution spectra of the C2 Swan system's 0-0 band from Comet P/Halley in March 1986 show that the populations of the upper state's rotational levels may be described by two rotational temperatures. The low rotational levels provide a low temperature, Trot = about 600 - 700 K. The higher levels correspond to about 3200 K. If a contribution from the 3200-K molecules is subtracted from the populations of the low-J-prime levels, the latter are characterized by Trot = about 190 K. A comparison with recent predictions for C2 molecules fluorescing in sunlight shows that the observed and predicted level populations are in good agreement for J-prime greater than about 15, but there is a sharp disagreement for the low rotational levels.
- Publication:
-
The Astrophysical Journal
- Pub Date:
- April 1990
- DOI:
- 10.1086/168654
- Bibcode:
- 1990ApJ...353..640L
- Keywords:
-
- Astronomical Spectroscopy;
- Carbon;
- Halley'S Comet;
- Spectral Bands;
- Swan Bands;
- Emission Spectra;
- High Resolution;
- COMETS;
- HALLEY;
- SPECTROSCOPY;
- CARBON;
- SPECTRA;
- TEMPERATURE;
- ROTATION;
- COMPARISONS;
- FLUORESCENCE;
- ABUNDANCE;
- EMISSIONS;
- EARTH-BASED OBSERVATIONS;
- STRUCTURE;
- WAVELENGTHS;
- INTENSITY;
- MOLECULES;
- ASTRONOMY;
- SOLAR EFFECTS;
- DISTANCE;
- Astrophysics; Comets;
- ABUNDANCES;
- COMETS