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29P Schwassmann Wachmann.jpg
The comet Schwassmann–Wachmann 1
(Spitzer infrared image in false colours)
Discovered by

Arnold Schwassmann

Arno Arthur Wachmann
Discovery date November 15, 1927
1908 IV; 1927 II; 1941 VI;
1957 IV; 1974 II; 1989 XV;
Orbital characteristics A
Epoch March 6, 2006
Aphelion 6.25 AU
Perihelion 5.722 AU
Semi-major axis 5.986 AU
Eccentricity 0.0441
Orbital period 14.65 a
Inclination 9.3903°
Dimensions 30.8 km[4]
Last perihelion July 10, 2004[1]
Next perihelion March 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 80 are known. 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.[7]

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.[8][9]
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. ^ "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
  8. ^ Trigo-Rodriguez et al., Outburst activity in comets, I. Continuous monitoring of comet 29P/Schwassmann-Wachmann 1 [1]
  9. ^ 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