Volume 381, Number 2, JanuaryII 2002
|Page(s)||703 - 708|
|Section||Celestial mechanics and astrometry|
|Published online||15 January 2002|
CN, NH, and dust in the atmosphere of comet C/1999 J3 (LINEAR)
Main Astronomical Observatory, Ukrainian Academy of Sciences, Kyiv, Ukraine
2 Isaac Newton Institute of Chile, Kiev Branch, Ukraine
3 Max-Planck-Institute for Aeronomy, Kaltenburg-Lindau, Germany e-mail: firstname.lastname@example.org
Corresponding author: P. P. Korsun, email@example.com
Accepted: 24 October 2001
Comet C/1999 J3 (LINEAR) was observed with 2 m telescope of the Pik Terskol Observatory on September 19, 1999. Narrow-band CCD images of the CN, NH2, and dust atmospheres were recorded with the Two-Channel focal reducer of the Max-Plank-Institute for Aeronomy. The distributions of the CN and NH2 molecules in the comet atmosphere were fitted with a Monte Carlo model. For the CN atmosphere the best agreement between observed and calculated surface profiles was reached with the CN photodissociation lifetime s and with the parent photodissociation lifetime s. This result indicates that HCN is the main source of the CN radicals in the atmosphere of comet C/1999 J3 (LINEAR). Regarding the NH2 radicals, there is no doubt that NH3 is the dominant source of this species in the comet atmosphere. The lifetimes s for NH2 and s for its parent are close to theoretical calculations. The gas-production rates of CN, mol s-1, and NH2, mol s-1 have also been determined. The appearance of the comet and the obtained data show that the comet is a gaseous one. The values are 21.6 cm for the blue spectral window and 23.4 cm for the red one. The normalized spectral gradient of the cometary dust is low, 4.0% per 1000 Å. The ratio log((/Q(CN)) = -24.25 indicates a very low dust to gas ratio as well.
Key words: comets: individual: C/1999 J3 (LINEAR) / molecular processes / methods: numerical
© ESO, 2002
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