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91P/Russell 3

Past, Present, and Future Orbits by Kazuo Kinoshita


     Kenneth S. Russell (U. K. Schmidt Telescope Unit, Siding Spring, Australia) discovered this comet on plates exposed with the 1.24-m Schmidt on 1983 June 14 and 15. He estimated the magnitude as 16 and said it exhibited a tail 3-4 arc minutes long. Is was then situated near the Aquila-Aquarius border. The comet was confirmed by J. Gibson (Palomar Observatory, California, USA) on June 17 when a photograph with the 1.22-m Schmidt indicated a nuclear magnitude of about 17 and a weak tail extending about 2 arc minutes toward the west.

Historical Highlights

  • A more precise magnitude estimate was obtained by T. Seki (Geisei, Japan) on June 18 and 21, when he gave the total brightness as 16.5. The comet faded slow and steady thereafter. Astronomers at Oak Ridge Observatory detected it for the final time on October 31, using the 1.5-m reflector.
  • Using the positions of Russell and Gibson extending over the period of June 14 to 20, Brian G. Marsden computed the first orbit and published it on June 24. He said a parabolic orbit left large residuals, so that it was apparent the comet was moving in a short-period orbit. He gave the perihelion date as 1982 November 20, the perihelion distance as 2.61 AU, and the orbital period as 6.76 years. Marsden added that the period was uncertain. Following the comet's final observation, the orbit was independently refined by Marsden and S. Nakano. They indicated a perihelion date of 1982 November 23, a perihelion distance of 2.51 AU, and an orbital period of 7.50 years.
  • The comet was next expected to return to perihelion during May of 1990. It was recovered on 1989 January 1 and 2, by Gibson. He said the CCD images obtained with the 1.5-m reflector indicated a nuclear magnitude near 20. He added that a faint coma about 5 arc minutes across was visible and contained a sharp central condensation. Gibson's precise measurements of the position indicated the predicted perihelion date required a correction of -0.36 day. James V. Scotti (University of Arizona) observed the comet with the Spacewatch 0.91-m telescope on 1989 November 18 and 19. He determined the magnitude as 21.0 to 21.4 and said the comet was stellar in appearance. The comet was followed until 1990 May 28, at which time Seki estimated the total magnitude as 16.
  • The comet was expected at perihelion during 1997 November during its next apparition and Scotti recovered it with the 0.91-m Spacewatch telescope on 1996 November 18. He determined the total magnitude as 21.3. The comet was observed by several observatories on a number of occasions during 1997 and 1998. On 1998 May 29 it was estimated as magnitude 18.0 by observers at the Astronomical and Geophysical Observatory at Modra. It was last seen on 1998 August 19 by observers at Le Creusot.
  • cometography.com