81P/Wild
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Comet Wild 2 (officially designated 81P/Wild) is a comet named after Swiss astronomer Paul Wild (pronounced Vilt), who discovered it in 1978.
It is believed that for most of its 4.5 billion-year lifetime, Wild 2 had a more distant and circular orbit. In 1974, it passed close to the planet Jupiter, whose strong gravitational pull altered the comet's orbit and brought it into the inner solar system. Its orbital period changed from 40 years to about 6 years, and its perihelion is now about one astronomical unit.
Wild 2 was studied on January 2, 2004 by a spacecraft named Stardust, which collected particle samples from the comet's coma, to be returned to Earth in 2006.
The 72 close-up shots taken from Stardust show a surface riddled with flat-bottomed depressions, with sheer walls and other features that range from very small to up to 2 kilometres across. The comet itself has a diameter of 5 kilometres. These features are believed to be caused by impact craters or gas vents. During Stardust's flyby, at least 10 gas vents were active.
Other photographs
External links
- Orbital data of Wild 2 (http://stardust.jpl.nasa.gov/comets/wildephem.html)
- IAU Ephemerides page for 81P (http://cfa-www.harvard.edu/iau/Ephemerides/Comets/0081P.html)de:Wild 2