G A R Y   W.   K R O N K ' S   C O M E T O G R A P H Y


Past, Present, and Future Orbits by Kazuo Kinoshita

A. Nakamura image of 59P exposed on 2000 February 4
Copyright © 2000 by A. Nakamura (Kuma Kogen Astronomical Observatory, Japan)

This CCD image was taken on 2000 February 4.56 UT, using a 0.60-m f/6 Ritchey-Chretien telescope.


     E. Kearns and Kiem King Kwee (Palomar Observatory, California, USA) were conducting a photographic search for the long-lost periodic comet Tempel-Swift. On a plate exposed on 1963 August 17.46, they found a cometary object in Taurus, near the border of Auriga and Perseus. They estimated the magnitude as 12 and described the comet as diffuse, without a central condensation. The tail was less than 1 degree long. The comet was confirmed on August 24.44 and August 24.46, when Elizabeth Roemer (U. S. Naval Observatory, Flagstaff station, Arizona) obtained a pair of 30-minute exposures with a 40-inch reflector. She estimated the magnitude as 16, and said the comet was diffuse, with a sharply condensed nucleus of magnitude 17.1. A narrow tail extended 0.5 arc minute toward the west. Although the comet had been reported as the lost periodic comet Tempel-Swift, Roemer's precise position revealed the comet's motion was not what would be expected for that comet. The Palomar astronomers had found a new comet.

Historical Highlights

  • B. G. Marsden used precise positions obtained during August 17 to 27, and published the first parabolic orbit on September 11. The perihelion date was determined as 1963 October 28.11. Following the acquisition of observations into October, Marsden published an elliptical orbit which indicated a perihelion date of December 9 and an orbital period of 8.48 years. Marsden said the comet had passed close to Jupiter during 1961. Starting in 1967 numerous astronomers have investigated the orbit of this comet. The perihelion date proved to be December 7.01, while the period was 8.95 years.
  • During the comet's discovery apparition the comet's brightness never topped the initial discovery estimate of magnitude 12. As 1964 began brightness estimates placed the comet between 12.5 and 13, and observations during March showed the comet fainter than magnitude 14. The comet was last seen on 1965 April 24, when Roemer photographed it with the 40-inch f/6.8 Ritchey-Chr¬étien reflector. She described it as "weak, rather diffuse image of [magnitude] 19.3 to 19.8."
  • Marsden and Kaare Aksnes investigated the orbit of this comet prior to its 1963 discovery. The computed two orbits and began running them backwards to examine the close encounter with Jupiter in 1961. Both orbits revealed the comet to have passed within 0.03 AU of Jupiter on 1961 November 13. The comet's previous orbit would have had an orbit with an orbital period of 50 or 51 years. These details were basically confirmed in 1968 by Grzegorz Sitarski (Institute of Astronomy, Polish Academy of Sciences, Warsaw).
  • Marsden and Aksnes, as well as Sitarski, supplied predictions for the 1972 apparition of this comet. Elizabeth Roemer and L. M. Vaughn (University of Arizona, USA) recovered this comet on two 60-minute exposures obtained with the 229-cm reflector at Kitt Peak on 1971 July 26.36. They estimated the magnitude as 20.0-20.5, and described the comet as essentially stellar. The indicated correction to one of the predictions by Marsden and Aksnes was -0.4 day. The comet was not consistently followed until the latter half of 1972. The brightness steadily increased when observations resumed, with average estimates of magnitude 14 in late November and 13 by late December. As 1973 began, the comet was apparently slightly brighter than 13th magnitude and displayed a coma 0.8 arc minute across. The comet began fading after January and was last seen on April 6.
  • Sitarski actually provided a prediction for the 1981 apparition back in 1975 which indicated a perihelion date of November 30.5. In 1979, the Reverend Cameron Dinwoodie and D. R. L. Jones provided a prediction for the British Astronomical Association Handbook that gave an almost identical date. The comet was recovered by T. Seki (Japan) on 1981 June 29.77. He estimated the magnitude as 18. Precise positions indicated the prediction of Dinwoodie and Jones required a correction of -0.12 day. The comet brightened and reached a magnitude slightly brighter than 14 during November and December. The coma diameter topped off at 0.7 arc minute. The comet was last seen on 1982 February 26.
  • The comet was next recovered on 1989 September 10.29 by J. Gibson, who used a CCD camera on the 1.5-m reflector at Palomar Observatory. He determined the magnitude as 19.9 and said there was a "stellar nucleus and a possible faint coma a few arcsec in diameter." The positions indicated the prediction required a correction of +0.07 day. The comet attained a maximum brightness of magnitude 13.5 during November and December 1990. It was followed until 1992 January 31, when James Scotti (Spacewatch) determined the magnitude as 22.2.
    [Perihelion Date=1999 September 16.34; Period=9.45 years]
  • K. Muraoka took positions from the period of 1971-1992, included full planetary perturbations, and solved for nongravitational effects. He predicted the comet would next pass perihelion on 1999 September 16.32.
  • Additional Images

    G. Rhemann image of 59P exposed on 1999 October 16
    Copyright © 1999 by Gerald Rhemann (Austria)

    The photograph is a 10-minute exposure taken on 1999 October 16.07 UT, using a 225/255/435mm Schmidt camera and Kodak TP6415 film. The comet was estimated as magnitude 15.5.