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142P/Ge-Wang

Past, Present, and Future Orbits by Kazuo Kinoshita

Discovery

     Ge Yong-Liang and Wang Qi (Xinglong Station of the Beijing Observatory, China) were conducting a survey for near-Earth asteroids with a 0.60-m Schmidt telescope. While stereoscopically examining plates, they compared a 15-minute exposure obtained on 1988 November 4.60 and an 8-minute exposure obtained on November 4.64, and found "a slowly moving, faint and fuzzy image with an estimated magnitude 16." They preliminarily accepted it as a faint comet.
     As soon as the report reached the Central Bureau for Astronomical Telegrams, notices were dispatched to other observatories for confirmation. Almost immediately, C. S. and E. M. Shoemaker (Palomar Observatory, California, USA) reported prediscovery images on plates exposed with the 0.46-m Schmidt telescope on October 11.48, October 11.52, and November 4.37. They estimated the magnitude as 16.5 in October and 16 in November, while the comet was always diffuse, with a strong condensation, but no tail.
     At the end of November, T. Kojima (YGCO Chiyoda Station, Japan) found prediscovery images on plates exposed on November 3.54 and November 3.58. He estimated the magnitude as 17.

Historical Highlights

  • The comet was estimated as 17 during November and December. The final observation came on December 13 and was obtained at Oak Ridge Observatory.
  • From the initial discovery positions, as well as the prediscovery ones from Palomar, Brian G. Marsden computed an elliptical orbit with a perihelion date of 1988 June 22.77, a perihelion distance of 2.392 AU, an inclination of 10.4°, and an orbital period of 9.91 years. Marsden added, "The poor distribution of observations introduces substantial uncertainty, but a parabolic solution seems out of the question." The orbit was further refined by Marsden after the acquisition of the pre-discovery images of Kojima and the Shoemakers. Following the comet's final observations, various computations revealed an orbital period of 11.37 to 11.39 years.
  • The comet was predicted to pass perihelion on 1999 June 26.86 by S. Nakano and 1999 June 27.01 by Kenji Muraoka. J. V. Scotti (Lunar and Planetary Laboratory, Arizona, USA) recovered the comet on 1999 September 15.44, while using the 0.9-m Spacewatch telescope. He gave the total magnitude as 20.3 and noted a coma 12 arc seonds across and a tail extending 0.53 arc minute in PA 266°. His precise positions indicated a prediction by S. Nakano required a correction of -5.5 days.
  • cometography.com