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218P/LINEAR

Past, Present, and Future Orbits by Kazuo Kinoshita

Independent recovery photo of 218P exposed on 2009 April 15 by G. Sostero, E. Prosperi, E. Guido, and P. Camilleri
Copyright © 2009 by G. Sostero, E. Prosperi, E. Guido, and P. Camilleri (Grove Creek Observatory, Australia)

Discovery

     M. Bezpalko reported the discovery of a comet on five images obtained with the 1.0-m reflector of the Lincoln Near Earth Asteroid Research (LINEAR) program (New Mexico, USA) on 2003 April 29. The earliest of these images was obtained on April 29.33, while the latest was obtained on April 29.38. The magnitude was generally between 18.8 and 19.0 during this period, while a tail extended toward PA 270 degrees. The first confirmation was obtained by J. E. McGaha (Grasslands Observatory, Arizona, USA) on April 30.25. His 62-cm reflector revealed a nuclear magnitude of 18.1-18.2.

Historical Highlights

  • The first orbit was published by Brian G. Marsden (Central Bureau for Astronomical Telegrams) on 2003 May 2. Using 37 positions obtained from 2003 April 29 to May 2, this revealed the comet was moving in a short-period orbit with a perihelion date of 2003 May 13.42 and a period of 5.78 years. A revision was published by Marsden on May 6. This used 66 positions obtained during the period of April 29 to May 5 and revealed a perihelion date of May 14.36 and a period of 5.90 years. Following the comet's recovery in 2009, a new orbit for the 2003 apparition revealed a perihelion date of May 14.31 and a period of 6.10 years.
  • Several observations were made shortly after the comet's recovery. G. J. Garradd (Tamworth, New South Wales, Australia) noted the comet appeared slightly diffuse on April 30.6. McGaha said his 30-cm reflector revealed a magnitude of 17.7-17.9 and a faint coma measuring 5" by 10" which was "aligned north-south, with uniform brightness and no apparent nuclear condensation or core" on May 2.2. J. G. Ries (McDonald Observatory, Texas, USA) photographed the comet using the 76-cm reflector on May 2.3. He gave the magnitude as 17.7-18.0 and noted a tail extending 20 arc seconds toward the region slightly south of west. The comet was last detected on 2003 August.
  • Apparition of 2009: This comet was recovered on a single image obtained by the LINEAR program on 2009 March 31. An independent recovery was obtained by Giovanni Sostero, Enrico Prosperi, Ernesto Guido, and Paul Camilleri (Remanzacco Observatory, Italy) using a remote-controlled telescope at Grove Creek Observatory (Trunkey, New South Wales, AUstralia) on 2009 April 15.60. They described the comet as a "diffuse coma about 15 arcsec in diameter, with a central condensation" of magnitude of 19.2. The comet was 8 arc minutes southeast of the predicted position.
  • cometography.com