108P/Ciffreo (0108P)


Type: Periodic Perihelion date: 10 September 2021 Perihelion distance (q): 1.7 Aphelion distance (Q) : 5.8 Period (years): 7.2 Eccentricity (e): 0.56 Inclination (i): 11.4 JPL orbit diagram COBS lightcurve Jacqueline Ciffreo (Caussols) discovered this comet on 8 November 1985 on plates exposed with the 0.9-m Schmidt. She described it as diffuse and estimated the magnitude as 10. She obtained a further image on 8 November. M. Koishikawa (Sendai Observatory, Ayashi Station) confirmed the discovery on 8 November when the comet was located at the edge of a photographic plate obtained using a 300mm lens. Observations within the week following the discovery revealed the comet's magnitude was slightly brighter than 12, with a coma about 2.5 arc minutes across and a tail two arc minutes long. Brian G. Marsden (Central Bureau for Astronomical Telegrams) officially announced the comet's discovery on 12 November and gave a parabolic orbit based on two days' observations. This indicated a perihelion date of 8 October 1985, a perihelion distance of 2.05 AU, and an inclination of 20 degrees. By 18 November enough observations had become available to enable Marsden's colleague Daniel W. E. Green to compute an elliptical orbit which indicated a perihelion date of 28 October 1985, a perihelion distance of 1.72 AU, and an orbital period of 7.81 years. Later revisions indicated a perihelion date of 30 October and an orbital period of 7.22 years. The comet was next expected to return to perihelion in early 1993. J. V. Scotti (Lunar and Planetary Laboratory, Arizona, USA) was using the Spacewatch telescope at Kitt Peak when he recovered the comet on 24 September 1992. He then noted the coma was 15 arc seconds across, while the tail extended 0.36 arc minute toward the west. From observations on that night, as well as on the 25th, he noted a total magnitude of 18.0 and a nuclear magnitude of 20.6. His precise positions indicated the predicted perihelion date needed a correction of +0.6 day, making it 23 January 1993. Following the announcement T. Seki (Geisei, Japan) found images on plates exposed on 26 August, 4 and 5 September. The comet was followed until 26 February 1993, when Scotti photographed it. He then determined the magnitude as 16.5. The comet was next expected at perihelion on 18 April 2000. It was recovered on 10 November 1999 by astronomers at Mount John Observatory in New Zealand. Although the comet was predicted to reach magnitude 17 during April 2000, no observations were made during the period of December 1999 through November 2000. Of the 15 positions submitted by astronomers during this apparition, only three included estimates of the comet's brightness. The brightest reported magnitude was about 19.5. Observations (VEMag = visual equivalent magnitude) Date 10x10 mag Error VEmag Coma ' 06-Sep-14 16.37 0.04 15.0 0.2 20-Sep-14 16.19 0.01 14.4 0.3 28-Sep-14 15.95 0.01 14.0 0.3 15-Oct-14 15.76 0.02 13.1 0.3 25-Oct-14 15.73 0.04 13.7 0.2 02-Nov-14 15.75 0.02 13.9 0.4 16-Nov-14 15.69 0.04 14.4 0.3 21-Aug-21 15.8 0.4 12-Sep-21 16.17 0.01 14.8 0.6