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29P Schwassmann Wachmann.jpg
The comet Schwassmann–Wachmann 1
(Spitzer infrared image in false colours)
Discovered byArnold Schwassmann
Arno Arthur Wachmann
Discovery dateNovember 15, 1927
1908 IV; 1927 II; 1941 VI;
1957 IV; 1974 II; 1989 XV;
Orbital characteristics A
EpochMarch 6, 2006
Aphelion6.25 AU
Perihelion5.722 AU
Semi-major axis5.986 AU
Orbital period14.65 a
Dimensions30.8 km[4]
Last perihelionJuly 10, 2004[1]
Next perihelionMarch 7, 2019[2][3]

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.[5] It was discovered photographically, when the comet was in outburst and the magnitude was about 13.[5] Precovery images of the comet from March 4, 1902, were found in 1931 and showed the comet at 12th magnitude.[5]

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 4 magnitudes.[6] This happens with a frequency of 7.3 outbursts per year,[6] fading within a week or two. The magnitude of the comet has been known to vary from 19th magnitude to 9th magnitude, a ten thousand-fold increase in brightness, during its brightest outbursts. Highly changing surface processes are suspected to be responsible for the observed behavior.[6]

The comet is thought to be a member of a relatively new class of objects called "centaurs", of which at least 400 are known.[7] These are small icy bodies with orbits between those of Jupiter and Neptune. Astronomers believe that centaurs are recent escapees from the Kuiper belt, a zone of small bodies orbiting in a cloud at the distant reaches of the Solar System. Frequent perturbations by Jupiter[4] will likely accumulate and cause the comet to migrate either inward or outward by the year 4000.[8]

The dust and gas comprising the comet's nucleus is part of the same primordial materials from which the Sun and planets were formed billions of years ago. The complex carbon-rich molecules they contain may have provided some of the raw materials from which life originated on Earth.

The comet nucleus is estimated to be 30.8 kilometers in diameter.[4]

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.[9][10]
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


  1. ^ 29P past, present and future orbital elements
  2. ^ Syuichi Nakano (January 29, 2012). "29P/Schwassmann-Wachman 1 (NK 2189)". OAA Computing and Minor Planet Sections. Retrieved 2012-02-18.
  3. ^ Patrick Rocher (February 4, 2012). "Note number : 0015 P/Schwassmann-Wachmann 1 : 29P". Institut de mécanique céleste et de calcul des éphémérides. Retrieved 2012-02-18.
  4. ^ a b c "JPL Close-Approach Data: 29P/Schwassmann-Wachmann 1" (last observation: April 10, 2009). Retrieved 2009-05-05.
  5. ^ a b c Kronk, Gary W. (2001–2005). "29P/Schwassmann-Wachmann 1". Archived from the original on October 22, 2008. Retrieved 2008-10-13. (Cometography Home Page)
  6. ^ a b c 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 2008-10-13.
  7. ^ "JPL Small-Body Database Search". Jet Propulsion Laboratory. Retrieved 13 August 2018.
  8. ^ "Twelve clones of 29P/Schwassmann-Wachmann diverging by the year 4000". Archived from the original on June 23, 2015. Retrieved 2009-04-30. (Solex 10) Archived April 29, 2009, at WebCite
  9. ^ Trigo-Rodriguez et al., Outburst activity in comets, I. Continuous monitoring of comet 29P/Schwassmann-Wachmann 1 [1]
  10. ^ Trigo-Rodriguez et al., Outburst activity in comets , II. A multi-band photometric monitoring of comet 29P/Schwassmann-Wachmann 1[2]

External links[edit]

Numbered comets
29P/Schwassmann–Wachmann Next