104P/Kowal (0104P)

Type: Periodic Perihelion date: 11 January 2022 Perihelion distance (q): 1.1 Aphelion distance (Q) : 5.3 Period (years): 5.7 Eccentricity (e): 0.67 Inclination (i): 5.7 JPL orbit diagram COBS lightcurve Charles T. Kowal (Palomar Observatory, California, USA) discovered this comet on photographic plates exposed with the 122-cm Schmidt telescope on 27, 28, and 29 January 1979. The plates exposed for dwarf galaxies. The comet was then estimated as magnitude 17. There was some slight condensation within the diffuse coma, but no tail was visible. Although the comet's brightness was not expected to exceed magnitude 15 during the 1997-1998 apparition, observations during November 1997 already revealed it over a magnitude brighter than expected. Observers frequently found the comet close to magnitude 13.5 throughout December, and by mid-January it had increased to about 13. The coma diameter always remained small from November through January, with estimates ranging from 0.8 to 1.6 arc minutes. Early in December of 2003, G. W. Kronk found that a previously unpublished comet discovery made by the Reverend Leo Boethin in January 1973 was a prediscovery observation of comet 104P. Boethin (Bangued, Philippines) found the comet with his 8-inch Newtonian reflector around 4 a.m. local time on 12 January 1973. He estimated the magnitude as 9.5 and measured the coma diameter as 7 arc minutes. He reobserved the comet the next morning and again noted the magnitude as 9.5. He said the coma was then 8 arc minutes across and exhibited a stellar nucleus. Boethin saw the comet one last time on 13 January, but said the brightness had faded to magnitude 13.0, near the limit of his telescope. The comet was reported to the Central Bureau for Astronomical Telegrams by letter. By the time it arrived, the moon made observations impossible and the comet was never seen after Boethin's final observation. Kronk found that comet 104P was within 2 arc minutes of Boethin's comet and was moving in the same direction, with the same rate of motion. He reported this information to the Central Bureau and noted the comet was probably fading from an outburst. B. G. Marsden found he was able to link Boethin's visual positions to those of 104P and found the perihelion date as 4 August 1972. He agreed with the scenario that the comet had undergone an outburst. Kazuo Kinoshita has examined the orbital evolution of this comet for the period of 1946 to 2022. He found the orbit had undergone very little change from 1946 until an approach of 0.9827 AU from Jupiter on 15 January 1996. This encounter reduced the perihelion distance from 1.50 AU to 1.40 AU and reduced the orbital period from 6.38 years to 6.18 years. The encounter was also a sign of things to come, as, following the next perihelion the comet passed 0.282 AU from Jupiter on 25 June 2007, reducing the perihelion distance from 1.40 AU to 1.17 AU and the orbital period from 6.19 years to 5.90 years. Still another encounter in 2019 further reduced the perihelion distance and orbital period. Observations (VEMag = visual equivalent magnitude) Date 10x10 mag Error VEmag Coma ' 05-Sep-21 18.8 0.4 31-Mar-22 12.5 4.1 30-Apr-22 16.60 0.04 14.3 1.5