Abstract A 40.6 cm Newtonian telescope has been interfaced to the Fabry-Perot interferometer at the Arecibo Observatory to make high spectral resolution measurements of Comet Halley emissions at 6562.72 Å (H-alpha) and 6300.3 Å (OI). In March 1986 the H-alpha surface brightness for a 5′.9 field of view centered on the comet nucleus decreased from 39±7.8 rayleighs on 12 March to 16±3.8 rayleighs on 23 March. The atomic hydrogen production rate on 12 March 1986 was 1.62±0.5 × 1030 s −1, and on 23 March 1986 it was 6.76±2.3 × 1029 s −1. Using spectral resolution of 0.196 Å, we found the atomic hydrogen outflow velocity to be approximately 7.9±1.0 km s −1. In general, the H-alpha spectra are highly structured, and indicative of a multiple component atomic hydrogen velocity distribution. An isotropic outflow of atomic hydrogen at various velocities is not adequate to explain the spectra measured at H-alpha. The 6300.3 Å emission of O(1D) had a surface brightness of 81±16 rayleighs on 15 March 1986, and 95±11 rayleighs on 17 March 1986. After adjustment for atmospheric extinction, the implied O(1D) production rate on 15 March is 6.44±3.0 × 1028 s −1, and the production rate on 17 March is 5.66±2.7 × 1028 s −1. These spectra included a feature at 6300.8 Å that we attribute to NH2. The brightness of this emission feature was 37±11 rayleighs on 15 March.
High spectral resolution Fabry-Perot interferometer measurements of comet Halley at H-alpha and 6300 Å
Advances in Space Research ; 5 , 12 ; 283-287
1985-01-01
5 pages
Aufsatz (Zeitschrift)
Elektronische Ressource
Englisch
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