The British Astronomical Association (BAA) announced that comet/centaur 29P/Schwassmann-Wachmann underwent an outburst of approximately three magnitudes on November 19, 2020. Richard Miles is coordinating a monitoring program for this object. Photometric observations by Jean-François Soulier, Nick James, and Denis Buczynski and others are plotted in the post by Nick James at the following link: https://britastro.org/node/25061
Additional observations are encouraged.
Interpreting the time axis of the plot:
Julian Date 2459100 = 2020-Sep-07 12:00:00 UT
Julian Date 2459173.28 = 2020-Nov-19 18:43:12 UT
Jean-François Soulier reported 29P magnitude on 2020-Nov-18 17:30 UT at nuclear magnitude 16.0 as posted on the French Lesia website.
Outbursts from 29P typically occur several times per year just as it has since its 1927 discovery by Arnold Schwassmann and Arno Arthur Wachmann at the Hamburg Observatory in Hamburg, Germany.
29P is a fun object to observe.
The coma typically develops an expansion shell that grows asymmetrically in size with time with expansion velocity near 0.13 km/s.
Many professional observers have studied 29P through the decades.
Elizabeth Roemer and Fred Whipple have written many papers on 29P.
29P has been observed with both the Hubble and Spitzer Space Telescopes.
The orbit of 29P is of low eccentricity or nearly circular such that heliocentric distance or time from perihelion does not seem to correlate with when it will outburst. It orbits in the centaur region between Jupiter and Saturn.
Packed Designation: 0029P
Perihelion Date T: 2019 03 18.0541 = JD 2458560.5541
Perihelion Distance q: 5.76772 AU
Semimajor axis a = 6.034925 AU
Aphelion distance Q: 6.302134 AU
Eccentricity e: 0.04428
Inclination: 9.3668 degrees
Argument of Perihelion: 48.5310 degrees
Longitude of Ascending Node: 312.3751 degrees
Reference: MPEC 2020-U96
Jupiter Tisserand Parameter Tj: 2.9853
Taken from orbital elements in MPC Comet.dat
There are several theories on the outburst mechanism, the size of it nucleus, and estimates of its rotational period.
Roemer, E., An Outburst of Comet Schwassmann-Wachmann 1, Publications of the Astronomical Society of the Pacific, Vol. 70, No. 414, p.272
Bibliographic Code: 1958PASP…70..272R
Whipple, F. L., Rotation and outbursts of comet P/Schwassmann-Wachmann 1, Astronomical Journal, vol. 85, Mar. 1980, p. 305-313.
Bibliographic Code: 1980AJ…..85..305W
Hosek, Matthew W., Jr.; Blaauw, Rhiannon C.; Cooke, William J.; Suggs, Robert M., Outburst Dust Production of Comet 29P/Schwassmann-Wachmann 1, The Astronomical Journal, Volume 145, Issue 5, article id. 122, 8 pp. (2013).
Bibliographic Code: 2013AJ….145..122H
Schambeau, Charles Alfred;Fernandez, Yanga R.; Samarasinha, Nalin H.; Kundu, Arunav; Analysis of Hubble Space Telescope Observations of an Outburst of Comet 29P/Schwassmann-Wachmann 1, American Astronomical Society, DPS meeting #48, id.#301.03 (10/2016)
Bibliographic Code: 2016DPS….4830103S https://ui.adsabs.harvard.edu/abs/2016DPS….4830103S/abstract
MPC observation/orbit database
JPL Small-Body Database Browser