VEGA three-channel spectrometer experiment: Spectroscopy of comet Halley in the visible and near-ultraviolet ranges
Abstract
A total of 3600 spectra of Comet Halley in the 275-710 nm were obtained on March, 8, 9, 10 and 11, 1986, from the VEGA 2 spacecraft. The emissions of OH, NH, CN, C3, CH, C2, NH2 and H2O+ are identified. From the OH intensity in the (0,0) band: 1.1 Megarayleigh at 5400 km from the nucleus, it can be inferred that the OH production rate was (1.4 +/- 0.5)×1030 molecules s-1. The NH, C3, CH and NH2 bands became comparatively more intense at distances from the nucleus shorter than 3000km. At 06:40 U.T. when the instrument field of view was 6000×4500 km, two jets were observed. Spectra from the jets show significant differences with other spectra. Inside a jet NH, C3 and NH2 are comparatively more intense and the rotational distributions of OH, CN and C2 are strongly distorted. This shows that part of the observed emissions probably comes from radicals directly produced in the excited state during the initial process of photolysis of the parent molecules.
- Publication:
-
Advances in Space Research
- Pub Date:
- 1985
- DOI:
- 10.1016/0273-1177(85)90078-X
- Bibcode:
- 1985AdSpR...5l.137M
- Keywords:
-
- Astronomical Spectroscopy;
- Halley'S Comet;
- Spaceborne Experiments;
- Ultraviolet Spectra;
- Vega Project;
- Visible Spectrum;
- Cometary Atmospheres;
- Cyanogen;
- Hydroxyl Emission;
- Photolysis;
- Astrophysics