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135P/Shoemaker-Levy 8

Past, Present, and Future Orbits by Kazuo Kinoshita


     This comet was discovered by Carolyn S. and Eugene M. Shoemaker and David H. Levy on photographic plates exposed with the 0.46-m Schmidt telescope at Palomar Observatory on 1992 April 5. The magnitude was determined as 17.0 and there was possibly a very faint tail towards the west. This team obtained confirming images on April 7 and 8.
     A few days after the discovery announcement, A. Savage (Siding Spring, Australia) found a prediscovery image obtained on a plate exposed with the 1.2-m U.K. Schmidt on March 30. It revealed a tail extending 30 arc seconds to the northwest.

Historical Highlights

  • The comet was officially announced by the Central Bureau for Astronomical Telegrams on April 9. The Palomar group had obtained enough positions to enable B. G. Marsden to compute a parabolic orbit with a perihelion date of 1992 October 28, a perihelion distance of 1.44 AU, and an inclination of 8 degrees. Marsden added, "It is quite likely that the comet is a short-period one." Following the acquisition of additional positions, including the prediscovery one from March 30, S. Nakano confirmed Marsden's suspicion by computing a short-period orbit with a perihelion date of 1992 May 21, a perihelion distance of 2.72 AU, and an orbital period of 7.59 years. Although the orbit was generally correct, the large perihelion distance made these early computations somewhat uncertain. Following the comet's final observations on 1993 September 16 revisions in the orbit revealed a perihelion date of June 13 and an orbital period of 7.47 years.
  • This comet was recovered on 1998 January 22 by C. W. Hergenrother. He was using the Smithsonian Astrophysical Observatory's 1.2-m reflector at Mt. Hopkins. The magnitude was given as between 21.7 and 22.0. The precise positions indicated the prediction required a correction of +0.03 day. Hergenrother confirmed the comet with the Lunar and Planetary Laboratory's 1.5-m reflector at the Catalina station on January 28. He said the coma appeared moderately diffuse and 5 arc seconds across.
  • cometography.com