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Discovery
Paul Wild (Astronomical Institute, Berne University, Switzerland) discovered this comet on exposures obtained with the 0.4-m Schmidt telescope at Zimmerwald. The photographic plates were exposed on 1980 April 11.08, April 11.94, and April 12.90. He estimated the magnitude as 15.5 and added that the comet was diffuse with a rather strong condensation. Since nearly a month had passed since the images were exposed, Wild made an attempt to recover it. The comet was found on a plate exposed on May 7.86. The brightness and appearance were unchanged since the April observations.
Historical Highlights
Both Wild and Brian G. Marsden determined the comet was moving in a short-period orbit. Marsden's calculations were first published on May 9 and revealed a perihelion date of 1980 October 6.30, a perihelion distance of 2.296 AU, and an orbital period of 6.90 years. Further observations did aid in refining the orbit, but Marsden's computations were very close because of the nearly one-month observational arc.
Marsden initially noted that the comet passed 0.13 AU from Jupiter during 1976 August. Prior to this encounter the perihelion distance had been 4.2 AU and the orbital period was 10.3 years.
The comet was moving toward the sun and away from Earth at the time of its discovery. Subsequently its brightness changed little. It was last detected on 1980 August 11.49, at which time the magnitude was estimated as 16.
S. Nakano took the available positions for this comet and computed a definitive orbit for the 1980 apparition. He subsequently integrated it forward and predicted the next perihelion would fall on 1987 August 31. T. Gehrels and J. V. Scotti (Lunar and Planetary Laboratory, University of Arizona, USA) recovered the comet on 1987 January 29.46 with the 0.91-m Spacewatch telescope. The total magnitude was then given as 19.5, while the diffuse coma was 14 arc seconds across. The precise positions indicated Nakano's prediction required a correction of +0.79 day. The comet was kept under observation until 1988 September 11.46, at which time the magnitude of the nuclear condensation was given as 21.
The comet was next expected to pass perihelion on 1994 July 21. Scotti and Gehrels recovered it with the 0.91-m Spacewatch telescope on 1994 February 10.49. The magnitude was given as between 20.7 and 21.2. The coma was then 12 arc seconds across and there was a tail extending 0.29 arc minute toward PA 292°. The magnitude of the nuclear condensation was determined as 22.3. The precise positions indicated the prediction required a correction of only +0.03 day. The comet was followed until 1997 December 30.32.
The comet last passed perihelion in 2001 and attained a magnitude of about 17.5 around the middle of the year.
cometography.com
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