73P/Schwassmann-Wachmann

Infobox Comet
name=73P/Schwassmann-Wachmann


discoverer= Arnold Schwassmann
Arno Arthur Wachmann
discovery_date=May 2, 1930
designations=1930 VI; 1979 VIII; 1990 VIII; 1994w
epoch=March 6, 2006
semimajor=3.063 AU
perihelion=0.9391 AU
aphelion=5.187 AU
eccentricity=0.6934
period=5.36 a
inclination= 11.3907°
last_p=June 6, 2006
next_p=

73P/Schwassmann-Wachmann, also known as Schwassmann-Wachmann 3, is a periodic comet in our solar system which is in the process of disintegrating.

Comet Schwassmann-Wachmann 3, one of the comets discovered by astronomers by Arnold Schwassmann and Arno Arthur Wachmann, working at the Hamburg Observatory in Bergedorf, Germany [1] , broke into fragments on its re-entry to the inner solar system, May 1, 2006, in a reaction triggered by the sun's heating the comet as it emerged from the frozen space of the outer solar system.

The comet's initial discovery was serendipity: the astronomers were exposing photographic plates in search of a minor planets, on photographs exposed for a minor planet survey, on May 2, 1930. The comet was lost after its 1930 apparition, but was observed several more times.

73P/Schwassmann-Wachmann has an orbital period of slightly less than 5 1/3 years so that it comes nearest to the Earth every 16 years. 73P was originally estimated to have a core diameter of 1100 meters.

Breakup

In 1995, 73P began to disintegrate. It was seen to break into five large pieces labelled 73P-A, B, C, D & E. As of March 2006, at least eight fragments were known: B, C, G, H, J, L, M & N. On April 18, 2006, the Hubble Space Telescope recorded [http://hubblesite.org/newscenter/newsdesk/archive/releases/2006/18/ dozens of pieces of fragments B and G] . It appears that the comet may eventually disintegrate completely and cease to be observable (as did 3D/Biela in the 19th century), in which case its designation would change from 73P to 73D.

The fragments were passing the Earth in late April and early May 2006, coming nearest to the Earth around May 12 at a distance of about 11.9 million km (7.4 million miles). That is a close pass in astronomical terms (0.08 AU) though nothing to be concerned about. In 1930 when it passed the Earth this close, there were meteor showers with as many as 100 meteors per minute. However, recent analysis by P. A. Wiegert et al. [Monthly Notices of the Royal Astronomical Society, Volume 361, p. 638 [http://www.blackwell-synergy.com/doi/abs/10.1111/j.1365-2966.2005.09199.x "The τ Herculid meteor shower and Comet 73P/Schwassmann–Wachmann 3"] P. A. Wiegert, P. G. Brown, J. Vaubaillon and H. Schijns] suggests that a recurrence of this spectacle is unlikely.

In 2022, the comet fragments are expected to pass nearer to the Earth than in 2006. It is currently unknown what their exact trajectory is. Many astronomers will be watching as the fragments pass in 2006 to calculate their various trajectories for future years. If the fragments continue to break up, it may become impossible to track the many fragments since each time a fragment splits, the resulting fragments acquire progressively divergent trajectories.

The comet was to be visited by the "CONTOUR" comet nucleus probe on June 18, 2006. Unfortunately, the probe broke up after the launch making the flyby impossible.

Image gallery

External links

* [http://hubblesite.org/newscenter/newsdesk/archive/releases/2006/18/ Hubble provides spectacular detail of a comet's breakup]
* [http://cometography.com/pcomets/073p.html 73P at Kronk's Cometography]
* [http://science.nasa.gov/headlines/y2006/24mar_73p.htm?list237669 Mini-comets approaching Earth] (NASA)
* [http://www.shadowandsubstance.com/ Orbit diagram animated of the comet passing through our inner solar system]
* [http://skytonight.com/about/pressreleases/3311241.html "Sky and Telescope" article]
* [http://www.spacetelescope.org/news/html/heic0605.html 73P/Schwassmann-Wachmann at ESA/Hubble]

Notes