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29P/Schwassmann–Wachmann

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29P/Schwassmann–Wachmann
The comet Schwassmann–Wachmann 1
(Spitzer infrared image in false colours)
Nasa
Discovery
Discovered byArnold Schwassmann
Arno Arthur Wachmann
Discovery dateNovember 15, 1927
Designations
1908 IV; 1927 II; 1941 VI;
1957 IV; 1974 II; 1989 XV;
Orbital characteristics
EpochMarch 6, 2006
Aphelion6.25 AU
Perihelion5.722 AU
Semi-major axis5.986 AU
Eccentricity0.0441
Orbital period14.65 a
Max. orbital speed12.7 km/s[1]
Inclination9.3903°
Last perihelionMarch 7, 2019[2]
Next perihelionFeb 18, 2035[1]
Physical characteristics
Dimensions60.4 ± 7.4 km[3]
12.1 ± 1.2 d

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.[4] It was discovered photographically, when the comet was in outburst and the magnitude was about 13.[4] Precovery images of the comet from March 4, 1902, were found in 1931 and showed the comet at 12th magnitude.[4] It reached the last perihelion on March 7, 2019.[5] It came to opposition in late December 2022.[6]

The comet is a member of a class of objects called "Centaurs", of which at least 500 are known.[7] 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[5] will likely accumulate and cause the comet to migrate either inward or outward by the year 4000.[8] 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.[9]

The comet nucleus is estimated to be 60.4±7.4 kilometers[3] in diameter.[5]

Outbursts

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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.[10] This happens with a frequency of 7.3 outbursts per year,[10] 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.[11] 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.[12]

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.[13][14]
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

References

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  1. ^ a b "Horizons Batch for 29P/Schwassmann–Wachmann 1 (90000393) 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.
  2. ^ 29P past, present and future orbital elements
  3. ^ a b Schambeau, C.; Fernández, Y.; Lisse, C.; Samarasinha, N.; Woodney, L. (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.
  4. ^ 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)
  5. ^ a b c "JPL Close-Approach Data: 29P/Schwassmann–Wachmann 1". Retrieved May 5, 2009.
  6. ^ "Opposition for 29P (90000394) in December 2022". JPL Horizons. Retrieved February 24, 2023.
  7. ^ "JPL Small-Body Database Search: orbital class (CEN)". Jet Propulsion Laboratory. Retrieved August 13, 2018.
  8. ^ "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
  9. ^ 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.
  10. ^ 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.
  11. ^ 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.
  12. ^ 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.
  13. ^ Trigo-Rodriguez et al., Outburst activity in comets, I. Continuous monitoring of comet 29P/Schwassmann–Wachmann 1 [1]
  14. ^ Trigo-Rodriguez et al., Outburst activity in comets , II. A multi-band photometric monitoring of comet 29P/Schwassmann–Wachmann 1 arXiv:1009.2381
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Numbered comets
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