User:Rfassbind/Unusual asteroid

In Planetary science, the term unusual object is used for a minor planet that possesses an unusual physical or orbital characteristic. For the Minor Planet Center (MPC), which operates under the auspices of the International Astronomical Union, any non-classical main-belt asteroid, which account for the vast majority of all minor planets, is an unusual minor planet. These include the near-Earth objects and Trojans as well as the distant minor planets such as centaurs and trans-Neptunian objects.

Other unusual objects
The MPC also lists a group of other unusual minor planets, which orbital characteristics do not fit those of the near-Earth and distant populations. There 801 of these objects in total, of which 84 are numbered, including 12 named objects:


 * 944 Hidalgo
 * 4587 Rees
 * 5335 Damocles
 * 6130 Hutton
 * 7096 Napier
 * 7604 Kridsadaporn
 * 8373 Stephengould
 * 9767 Midsomer Norton
 * 20461 Dioretsa
 * 37117 Narcissus
 * 308306 Dainere
 * 365756 ISON

History
During the 1930s, two astronomers set up in competition to see who could discover the most unusual asteroid. Those in the main belt usually have more or less circular orbits. However, if the orbit becomes smaller and more elliptical, then asteroids can draw close to - or even collide with - the inner planets. Eugene Delporte, in Belgium, made the first discovery in March 1932 when he discovered asteroid 1221 Amor. This space rock spends over half its orbit outside the main belt and actually crosses Mars's orbit. It comes close to Earth's orbit before heading back out again. The very next month, Karl Reinmuth, in Heidelberg, discovered 1862 Apollo. This asteroid spends much less time in the main belt, spending most of its time inside Mars's orbit. In fact, Apollo crosses the Earth's orbit too.
 * 433 Eros?
 * In 1906, discovery of 588 Achilles, followed by 617 Patroclus a few months later, and by 624 Hektor the largest of all Jupter trojans in 1907

Characteristics

 * Damocloid
 * Extinct comet, are considered unusual minor planets in having the orbital characteristics of a long period, Jupiter-family or Halley-type comet but showing no sign of cometary activity.

Items:
 * 1996 PW (TNO, LPC)
 * 1998 WU24 (CEN, HTC)
 * (33342) 1998 WT24 (NEO)
 * 2011 YU75 (CEN)