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175P/Hergenrother

Past, Present, and Future Orbits by Kazuo Kinoshita

2MASS photo of 175P exposed on 2000 March 14
Copyright 2000 by University of Massachusetts

This image was taken by the Two Micron All Sky Survey (2MASS) on 2000 March 14.20. It was obtained with a 3-array Near Infra-Red Camera and Multi-Object Spectrometer attached to the 1.3-m Cassegrain telescope at Cerro Tololo Inter-American Observatory in Chile. This image was obtained in the J band (1.25 m). Atlas Image obtained as part of the Two Micron All Sky Survey (2MASS), a joint project of the University of Massachusetts and the Infrared Processing and Analysis Center/California Institute of Technology, funded by the National Aeronautics and Space Administration and the National Science Foundation.

Discovery

     C. W. Hergenrother (Lunar and Planetary Laboratory, Arizona, USA) discovered this comet with the 0.41-m f/3 Schmidt telescope in the course of the Catalina Sky Survey on 2000 February 4.46. He determined the magnitude as 17.1. One of the four CCD images revealed a tail extending 11 arc seconds toward PA 300°. Prediscovery observations were found on Lincoln Laboratory Near-Earth Asteroid Research (LINEAR) project images made on January 4.45, January 4.46, January 8.45, January 8.47, January 8.50, and January 8.52. The LINEAR images indicated nuclear magnitudes ranging from 18.7 to 19.4.

Historical Highlights

  • The first orbit released for this comet was an elliptical one computed by G. V. Williams (Central Bureau for Astronomical Telegrams), which utilized the prediscovery positions, as well as the initial follow-up positions obtained through February 6. The result was a perihelion date of 2000 March 18.73 and a period of 6.72 years.
  • The initial follow-up observations by various observers from around the world indicated total magnitudes ranging from 17.6 to 18.7. The coma diameter was generally given as 6" to 12" across, while the tail extended anywhere from 10 arc seconds to about 3 arc minutes toward PA 290°, depending on the type of telescope and CCD camera used. The comet attained a maximum magnitude of 16 or slightly brighter during late March and then began fading as it moved away from both the sun and Earth. The comet was last detected on June 6.51 by A. Nakamura (Kuma Kogen Observatory, Japan).
  • Following the final observations of this comet, Patrick Rocher determined the orbit of this comet. Rocher used 190 positions obtained during the period spanning 2000 January 4 to June 6. He determined the perihelion date as 2000 March 19.86 and the orbital period as 6.63 years. He estimated the period's uncertainty as ±0.0434 day. Using 170 positions spanning the same period of time, S. Nakano determined the perihelion date as March 19.87 and the period as 6.63 years. During April of 2003, Nakano took 172 positions and determined a marginally different orbit that essentially produced the same perihelion date and period.
  • In June of 2000, Nakano applied perturbations by Mercury to Neptune, as well as the minor planets Ceres, Pallas, and Vesta, to his orbit for the comet's 2000 apparition. He predicted the comet would next return to perihelion on 2006 November 6.93. During April of 2003, he slightly revised this to November 6.92.
  • cometography.com