81P/Wild

Wild 2 (official name 81P/Wild ) is a short- period comet, named after the Swiss astronomer Paul Wild, of which he was discovered on January 6, 1978. The comet was examined in January 2004 by NASA's Stardust spacecraft.

Orbit

It is believed that Wild 2 during its more than 4.5 billion years continuous existence of another and less eccentric orbit than it does today. After being approached in 1974 to around 0,006 AE to the planet Jupiter, whose strong gravitational forces affecting the orbit of the comet. As a result of this path fault he was deflected into the inner solar system: Its orbital period was shortened from forty to about six years, and its perihelion distance was reduced from about 5 AU only 1.591 AU. The aphelion of its orbit is since 5.306 AU and its orbital inclination 3.240 °.

Stardust spacecraft

Wild 2 was investigated on 2 January 2004 by the Stardust spacecraft. She collected particle samples from the coma and has these returned on 15 January 2006 on the investigation on the ground. Thus, it was first possible to examine material from a comet, which is likely to have changed little since the formation of the solar system, directly in terrestrial laboratories. An investigation of the comet dust by A'Hearn, Brownlee et al., Keller et al. and Zolensky et al. and summarized by Vivien Gornitz in the "Mineral News" in January 2007 showed that the dust contains the minerals anorthite, cubanite, diopside, iron, enstatite, forsterite, gehlenite, corundum, Osbornit, pentlandite, perovskite, spinel and pyrrhotite.

After further investigation, in 2009, the amino acid glycine detected.

The 72 close-ups, which were made of Stardust, show a cometary nucleus with around 5 km in diameter and an albedo of 0.04. Its rough surface with shallow wells plated, but the edges are steep and rugged. Apart from very small to even up to two kilometers reveal large structures. It is believed that these structures represent impact craters or were formed by outflowing gas jets. During the flyby of Stardust at least ten gas jets were active.