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185P/Petriew

Past, Present, and Future Orbits by Kazuo Kinoshita

Kusnirak and Pravec photo of 185P exposed on 2001 August 20
Copyright © 2001 by P. Kusnirak and P. Pravec

This image was obtained by Peter Kusnirak and Petr Pravec (Ondrejov Observatory, Czech Republic) on 2001 August 20.08. The image was obtained with a 65-cm reflector and a CCD camera. The image displays three representations of the same image of this comet. The large, left-hand image is the original, untouched image. The two right-hand images display the brightness contours within the coma and tail. The vertical streaks extending above and below some stars are simply a CCD artifact that occurs when starlight is overexposed on a CCD chip.

Discovery

Vance Avery Petriew (Regina, Saskatchewan, Canada) was observing with a 0.51-m reflector at a star party at Cyprus Hills, Saskatchewan, when he discovered this comet on 2001 August 18.42. It was then near the star Beta Tauri, near the border of Taurus and Auriga. In an email to German amateur astronomer Maik Meyer, Petriew said the comet was discovered accidentally because of a mistake. He was looking for the Crab Nebula and had actually started from the wrong star in Taurus. Petriew described the comet as 3 arc minutes in diameter and condensed. The magnitude was estimated as 11. The comet was quickly confirmed by R. Huziak and P. Campbell at Cyprus Hills with smaller telescopes. After an announcement was made to the Central Bureau for Astronomical Telegrams, a request was made for a more official confirmation. A. Hale (New Mexico) responded with several precise positions on August 19. His CCD camera revealed a magnitude of 13.0-13.4. Visually, Hale said the comet was magnitude 11.0, with a diameter of 2.5 arc minutes.

Historical Highlights

  • The comet was very quickly identified as a periodic comet, with the first orbits published on August 21. These indicated periods of 4.60 years (K. Kinoshita) and 5.51 years (B. G. Marsden). As further positions were obtained, the period was found to be 5.50 years. The comet appears to have passed 0.15 AU from Jupiter on 1982 July 6. The perihelion distance was then changed from 1.37 AU to 1.00 AU.
  • Many observers were initially placing the comet's brightness between 10.5 and 11 in the days following discovery, but the comet continued to brighten and was near magnitude 10 by the end of August. The diameter of the coma typically fell within the range of 2 to 4 arc minutes, with the size closely correlating with the size of the instrument used to observe the comet. The degree of condensation remained moderate. Although no tail was visually seen, a short, narrow tail was detected by observers using CCD cameras.
  • The comet was recovered at Zvezdno Obshtestvo Observatory (Plana), by F. Fratev, E. Mihaylova, and A. Kirchev, on 2007 January 11.69. Using a 25-cm reflector and a CCD camera they obtained twenty-nine 10-second exposures which revealed a diffuse coma 0.2 arc minutes across, with a total magnitude of 16.1.
  • Additional Images

    Giovanni Sostero image of 185P exposed on 2001 August 21
    Copyright © 2001 by G. Sostero

    This image was obtained by G. Sostero (Remanzacco Observatory, Italy) on 2001 August 21.08. The image was composed of 4 30-second exposures obtained with a 0.3-m f/2.8 Baker-Schmidt and a Hi-Sis 24 CCD camera. The image was reversed to better illustrate the comet's appearance.


    Gianluca Masi image of 185P exposed on 2001 August 21
    Copyright © 2001 by Gianluca Masi

    This image was obtained by G. Masi (Ceccano, Italy) on 2001 August 21.12. It was artificially colored by Masi to bring out details in the comet. The image was obtained with a 28-cm f/6.3 Schmidt-Cassegrain and an SBIG ST7 CCD camera.


    Giovanni Sostero photo of 185P exposed on 2001 August 22
    Copyright © 2001 by G. Sostero

    This image was obtained by G. Sostero (Remanzacco Observatory, Italy) on 2001 August 22.03. The image was composed of 10 30-second exposures obtained with a 0.3-m f/2.8 Baker-Schmidt and a Hi-Sis 24 CCD camera. The image was reversed to better illustrate the comet's appearance. The comet was then displaying a tail extending 2 arc minutes toward PA 283°.


    Konrad Horn photo of 185P exposed on 2001 August 22
    Copyright © 2001 by K. Horn and G. Neumann

    This image was obtained by Konrad Horn and Gerhard Neumann (Salem, Germany) on 2001 August 22.09. The image was composed of 30 60-second exposures obtained with a Genesis 100/500 telescope and an AUDINE CCD camera. The comet was then displaying a tail extending 6 arc minutes toward PA 276°.


    Image of 185P exposed on 2007 January 11
    Copyright © 2007 by F. Fratev, E. Mihaylova, and A. Kirchev (Sofia, Bulgaria)

    F. Fratev, E. Mihaylova, and A. Kirchev recovered this comet on 2007 January 11.69, while using the 25-cm reflector at Zvezdno Obshtestvo Observatory (Plana). This is a stack of twenty-nine 10-second exposures made with a CCD camera.

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