12P/Pons-Brooks (0012P)

Type: Periodic Perihelion date: 21 April 2024 Perihelion distance (q): 0.8 Aphelion distance (Q) : 33.6 Period (years): 71.2 Eccentricity (e): 0.95 Inclination (i): 74.2 JPL orbit diagram COBS lightcurve Jean Louis Pons (Marseille, France) discovered this comet on 21 July 1812, located in Lynx. Pons described it as a small, ill-defined nebulosity, without a tail, and not visible to the naked eye. Independent discoveries were made by Wisniewsky (Russia) on 1 August and Bouvard (France) on 2 August. The comet became visible to the naked eye on 13 August, and by the end of August it was displaying a tail about 2 degrees long. The comet probably reached its maximum brightness around mid-September, with a magnitude around 4 and was last seen on 28 September as its southern motion took it out of sight below the southern horizon. Estimates of the orbit period ranged from 65 to 75 years. Johann Encke determined a definitive orbit with a period of 70.68 years. This orbit was used to generate an ephemeris for the 1883 return, but searches were unsuccessful. William R. Brooks (Phelps, New York) accidentally “discovered” this comet on 2 September 1883. He described it as small and estimated the magnitude as 10. The comet remained a small, tailless nebulosity, but observations on 23 September revealed a rapid, unusual change had occurred as the comet had become a stellar object of magnitude 7 or 8. Thereafter, the coma reappeared, in addition to a short tail. The comet went back to normal and continued its expected brightening, attaining naked-eye visibility on 20 November. As January began it reached its greatest brightness of magnitude 3. Muller (Germany) noted a 0.7-magnitude brightening of the nucleus during 1.75 hours on 1 January 1884 and several astronomers reported the comet brightened by one magnitude on 19 January. The comet steadily faded thereafter and was last seen on 2 June at magnitude 9.5. Elizabeth Roemer (Lick Observatory) recovered the comet on 20 June 1953 at a magnitude of 17.5. As with the 1883-4 apparition, the comet experienced several outbursts in brightness. The first on 1 July brought the comet up to magnitude 13. The comet was back to its predicted brightness of 18 by 16 July and a slow brightening set in as the comet approached perihelion. By 15 September the comet had finally reached magnitude 16, but another outburst took the comet up to magnitude 12 by the 28th. Another outburst in occurred in December and then the comet performed as expected thereafter, reaching maximum magnitude of 6 during late April. Observations (VEMag = visual equivalent magnitude) Date 10x10 mag Error VEmag Coma ' 11-Jun-23 17.7 0.4 22-Jun-23 17.5 0.4 30-Jun-23 17.7 0.4 08-Jul-23 17.4 0.4 19-Jul-23 16.8 0.4 23-Jul-23 11.7 1.5 25-Jul-23 11.9 1.5 28-Jul-23 11.9 2.1 07-Aug-23 12.0 3.4 09-Aug-23 12.3 3.0 16-Aug-23 12.7 3.0 18-Aug-23 12.5 3.6 21-Aug-23 12.8 3.4 24-Aug-23 14.1 2.1 28-Aug-23 14.4 0.4 13-Sep-23 14.5 1.7 27-Sep-23 13.6 2.4 06-Oct-23 11.6 2.1 14-Oct-23 11.6 3.8 24-Oct-23 11.7 4.1 02-Nov-23 10.6 4.5 12-Nov-23 10.7 5.1 17-Nov-23 8.3 7.7