29P/Schwassmann–Wachmann

29P/Schwassmann–Wachmann
29P/Schwassmann–Wachmann imaged by Gemini Observatory in 2021
Discovery
Discovered byArnold Schwassmann
Arno Arthur Wachmann
Discovery siteHamburg Observatory
Discovery dateNovember 15, 1927
Designations
P/1902 E1; P/1927 V1
1908 IV; 1927 II; 1941 VI;
1957 IV; 1974 II; 1989 XV
Orbital characteristics[4]
EpochJanuary 1, 2023 (JD 2459945.5)
Observation arc13.83 years
Earliest precovery date4 March 1902
Number of
observations		622
Aphelion6.318 AU
(30 September 2026)[1]
Perihelion5.777 AU
Semi-major axis6.047 AU
Eccentricity0.0447
Orbital period14.87 years
Max. orbital speed12.7 km/s
Inclination9.364°
312.39°
Argument of
periapsis		50.913°
Last perihelionMarch 7, 2019[2]
Next perihelionFebruary 18, 2035[3]
TJupiter2.986
Earth MOID4.781 AU
Jupiter MOID0.792 AU
Physical characteristics[6]
Dimensions60.4 ± 7.4 km (37.5 ± 4.6 mi)
12.1 ± 1.2 days
0.033
Comet total
magnitude (M1)		10.1
~14[5]

Comet 29P/Schwassmann–Wachmann, also known as Schwassmann–Wachmann 1, was discovered on November 15, 1927, by Arnold Schwassmann and Arno Arthur Wachmann at the Hamburg Observatory in Bergedorf, Germany.[7] It is well known for being observable throughout the whole orbit and having frequent outbursts. The most recent outbursts were in May 2025, December 2025, and February 2026. The comet will next come to opposition on 11 March 2026,[8] and then come to aphelion on 30 September 2026.[1] It crossed the celestial equator in late 2025 and is headed further into southern skies until April 2029 when it will have a declination of −31.[9]

Discovery

It was discovered photographically, when the comet was in outburst and the magnitude was about 13.[7] Precovery images of the comet from March 4, 1902, were found in 1931 and showed the comet at 12th magnitude.[7]

Orbit and physical properties

The comet reached its most recent perihelion on March 7, 2019.[4] It spends its entire orbit just beyond Jupiter at 5.8–6.3 AU from the Sun where the comet remains active with a coma as it is close to the snow line. It will reach aphelion on 30 September 2026.[1]

The comet is a member of a class of objects called "centaurs", of which at least 500 are known.[10] These are small icy bodies with orbits between those of Jupiter and Neptune. The centaurs have been recently perturbed inward from the Kuiper belt, a disk of trans-Neptunian objects occupying a region extending from the orbit of Neptune to approximately 50 AU from the Sun. Frequent perturbations by Jupiter[4] will likely accumulate and cause the comet to migrate either inward or outward by the year 4000.[11] A number of centaurs appear to be dynamically and perhaps even physically related to 29P; such objects may traverse the coma of 29P when in outburst.[12]

The comet nucleus is estimated to be 60.4±7.4 kilometers in diameter.[4][6]

Outbursts

The comet is unusual in that while normally hovering at around 16th magnitude, it suddenly undergoes an outburst. This causes the comet to brighten by 1 to 5 magnitudes.[13] This happens with a frequency of 7.3 outbursts per year,[13] fading within a week or two. The magnitude of the comet has been known to vary from 18th magnitude to 10th magnitude, a more than thousand-fold increase in brightness, during its brightest outbursts. On 14 January 2021, an outburst was observed with brightness from 16.6 to 15.0 magnitude, and consistent with the 7.3 outbursts per year noted earlier.[14] Outbursts are very sudden, rising to maximum in about 2 hours, which is indicative of their cryovolcanic origin; and with the times of outburst modulated by an underlying 57-day periodicity possibly suggesting that its large nucleus is an extremely slow rotator.[15]

Comet 29P after outburst, this is a stack of 20 images centered on the comet's movement, frames taken with a 0.40m telescope F10 + CCD at La Cañada Observatory (MPC-J87) 04-Oct-2008 02:24 UT the stacked images have been Larson–Sekanina filtered to enhance the details, on the left a radial process with delta = −1 px to better show the expanding shells of gas and dust, on the right a rotational gradient with alpha=15 degrees displaying various jets.[16][17]
Comet 29P photographed at Ka-Dar Observatory
Comet 29P photographed at Ka-Dar Observatory
The quasi-circular orbit of 29P/Schwassmann–Wachmann compared to Jupiter and Saturn
The quasi-circular orbit of 29P/Schwassmann–Wachmann compared to Jupiter and Saturn

During 2025, there were 8 notable outbursts occurring as four pairs of twin events: January 2/6, February 1/2, May 13/25, and December 4/11. The December outburst reached about magnitude 13.[18] In 2026, there was an outburst on February 9 to magnitude 12.6V.[19]

References

  1. ^ a b c "Horizons Batch for 29P/Schwassmann–Wachmann 1 (90000395) on 2026-Sep-30" (Aphelion occurs when rdot flips from positive to negative). JPL Horizons. Retrieved September 29, 2025.
  2. ^ 29P past, present and future orbital elements
  3. ^ "Horizons Batch for 29P/Schwassmann–Wachmann 1 (90000395) on 2035-Feb-18" (Perihelion occurs when rdot flips from negative to positive). JPL Horizons. Archived from the original on June 17, 2022. Retrieved October 1, 2021.
  4. ^ a b c d "29P/Schwassmann–Wachmann 1 – JPL Small-Body Database Lookup". ssd.jpl.nasa.gov. Jet Propulsion Laboratory. Retrieved May 5, 2009.
  5. ^ Yoshida: 29P (2012–2026)
  6. ^ a b C. A. Schambeau; Y. R. Fernández; C. M. Lisse; N. Samarasinha; L. M. Woodney (2015). "A new analysis of Spitzer observations of Comet 29P/Schwassmann–Wachmann 1". Icarus. 260: 60–72. arXiv:1506.07037. Bibcode:2015Icar..260...60S. doi:10.1016/j.icarus.2015.06.038. S2CID 119298410.
  7. ^ a b c Kronk, Gary W. (2001–2005). "29P/Schwassmann–Wachmann 1". Archived from the original on October 22, 2008. Retrieved October 13, 2008. (Cometography Home Page)
  8. ^ "Opposition for 29P (90000394) in March 2026". JPL Horizons. Retrieved January 3, 2026.
  9. ^ "Maximum Southern Declination in April 2029". JPL Horizons. Retrieved February 14, 2026.
  10. ^ "JPL Small-Body Database Search: orbital class (CEN)". Jet Propulsion Laboratory. Retrieved August 13, 2018.
  11. ^ "Twelve clones of 29P/Schwassmann–Wachmann diverging by the year 4000". Archived from the original on June 23, 2015. Retrieved April 30, 2009. (Solex 10) Archived December 20, 2008, at the Wayback Machine
  12. ^ de la Fuente Marcos, C.; de la Fuente Marcos, R.; Licandro, J.; Serra-Ricart, M.; Martino, S.; de Leon, J.; Chaudry, F.; Alarcón, M. R. (May 13, 2021). "The active centaur 2020 MK4". Astronomy & Astrophysics. 649 (1): A85 (15 pages). arXiv:2104.01668. Bibcode:2021A&A...649A..85D. doi:10.1051/0004-6361/202039117. S2CID 233024896.
  13. ^ a b Trigo-Rodríguez; Melendo; García-Hernández; Davidsson; Sánchez (2008). "A continuous follow-up of Centaurs, and dormant comets: looking for cometary activity" (PDF). European Planetary Science Congress. Retrieved October 13, 2008.
  14. ^ Lin, Zhong-Yi; et al. (January 15, 2021). "ATel #14323: Outburst of comet 29P/Schwassmann–Wachmann 1". The Astronomer's Telegram. Retrieved January 15, 2021.
  15. ^ Miles, Richard (July 1, 2016). "Discrete sources of cryovolcanism on the nucleus of Comet 29P/Schwassmann–Wachmann and their origin". Icarus. 272: 387–413. Bibcode:2016Icar..272..387M. doi:10.1016/j.icarus.2015.11.011.
  16. ^ Trigo-Rodriguez et al., Outburst activity in comets, I. Continuous monitoring of comet 29P/Schwassmann–Wachmann 1 [1]
  17. ^ Trigo-Rodriguez et al., Outburst activity in comets, II. A multi-band photometric monitoring of comet 29P/Schwassmann–Wachmann 1 arXiv:1009.2381
  18. ^ 29P: Twin strong outbursts (11 Dec 2025)
  19. ^ Amongst the 5 brightest eruptions (10 February 2026)


allikas: https://en.wikipedia.org/wiki/29P/Schwassmann-Wachmann