99P/Kowal (0099P)

Type: Periodic Perihelion date: 12 April 2022 Perihelion distance (q): 4.7 Aphelion distance (Q) : 7.5 Period (years): 15.1 Eccentricity (e): 0.23 Inclination (i): 4.3 JPL orbit diagram COBS lightcurve Charles T. Kowal (Palomar Observatory, California, USA) discovered this comet on a photographic plate exposed with the 122-cm Schmidt telescope on 24 April 1977. He estimated the magnitude as 16 to 17, and described the comet as diffuse with some condensation and a tail extending 2 arc minutes toward the northeast. It was then in Virgo. Images also appeared on plates exposed with the same telescope on the 25th and 26th. The comet was already passed perihelion when found and remained visible until 17 June, when near magnitude 19. Using observations obtained from 24 April through 19 May, B. G. Marsden computed an elliptical orbit with a period of 18.6 years. As further observations were obtained the period was revised. During 1979 Marsden gave the period as 15.11 years and said the short observational arc brought about an uncertainty of about 2 weeks. S. Nakano provided a prediction for the expected 1992 return. He determined the perihelion date as 12 June 1992 and gave the orbital period as 15.08 years. J. V. Scotti, using the Spacewatch telescope at Kitt Peak, recovered the comet on 21 February 1991. Then at magnitude 18.4, the precise position indicated an actual perihelion date of 10 March 1992 and an orbital period of 15.02 years. The comet was then exhibiting a coma 15 arc seconds across and a tail extending 29 arc seconds in PA 297°. The comet was followed until 25 April 1992. Observations (VEMag = visual equivalent magnitude) Date 10x10 mag Error VEmag Coma ' 10-Mar-22 17.7 0.4 30-Mar-22 17.4 0.4 08-Apr-22 17.0 0.4 24-Apr-22 17.2 0.4 02-May-22 17.31 0.08 17.0 0.4 21-May-22 17.5 0.4 22-May-22 17.3 0.4 29-May-22 17.7 0.4 31-May-22 17.8 0.4 17-Jun-22 17.4 0.4 03-Jul-22 17.6 0.4 14-Jul-22 17.9 0.4