172P/Yeung

Past, Present, and Future Orbits by Kazuo Kinoshita

Discovery      William Kwong Yu Yeung (Desert Eagle Observatory, Benson, Arizona, USA) discovered this "apparently asteroidal object" on 2002 January 21.49, using a charge-coupled-device (CCD) electronic-camera attached to his 45-cm reflector. The stellar image had a magnitude of 20.4. He obtained additional images on January 22 and 23. It received the preliminary designation of "2002 BV". During early April, Yeung noted that his new object was still listed as having astrometry from only three days, so despite the fact that it should have been brightening, no additional positions were obtained. He contacted T. Spahr (Whipple Observatory, Mt. Hopkins). Spahr found that positions were available from Lincoln Laboratory ETS (New Mexico, USA) for February, March, and April. These positions allowed him to identify additional asteroidal images that had been reported during 1998 (Steward Observatory, Kitt Peak, Arizona, USA) and 2000-2001 (Lincoln Laboratory ETS). The 2001 positions spanned nearly a month and the object received the preliminary minor planet designation "2001 CB40". Spahr noted the "unusual nature of the orbit" and, together with M. Calkins, he obtained unfiltered CCD observations on May 5, 6, and 7, using the 1.2-m reflector. The images revealed the object was larger that the nearby stars, while a faint tail extended 5 arc seconds in PA 315¡. The total magnitude was given as 17. Historical Highlights The first orbit released after the object was identified as a comet, was an elliptical one. It was computed by D. W. E. Green (Central Bureau for Astronomical Telegrams) and published on IAU Circular 7896 (2002 May 9). Based on positions spanning the period of 1998 October 12 to 2002 May 7, he determined the perihelion date as 2002 March 11.06 and the perihelion distance as 2.24 AU. The comet was observed by P. C. Sherrod (Arkansas, USA) on 2002 July 7 and 8. On the first date, he gave the magnitude as 16.44 and noted a coma 8" across. On the last date, he gave the magnitude as 17.12 and noted a coma 10-12" across. A. Nakamura (Kuma Kogen Observatory, Japan) observed the comet on several occasions during the period spanning 2003 October 1 to 24. He noted the magnitude was between 19.8 and 20.2. The comet was last detected on 2003 November 19, when L. Buzzi (Schiaparelli Observatory) photographed it using a 60-cm reflector and a CCD camera. He gave the magnitude as 20.1. The comet was recovered by E. Beshore (Mt. Lemmon Survey) using the 1.5-m reflector and a CCD on 2005 October 3.45. The total magnitude was then given as 20.1. The comet was last observed at Steward Observatory (Kitt Peak, Arizona, USA) on 2005 November 10. The total magnitude was given as 20.4. cometography.com