2060 Chiron
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2060 Chiron (pronounced /ˈkaɪrən/ kye'-rən, from Greek: Χείρων) is a planetoid in the outer solar system. Discovered in 1977 by Charles T. Kowal (precovery images have been found as far back as 1895),[5] it was the first known member of a new class of objects now known as centaurs, with an orbit between those of Saturn and Uranus. Although it was initially classified as an asteroid, later dispute arose as to whether it was an asteroid or actually a comet. Today it is classified as both, and accordingly it is also known by the cometary designation 95P/Chiron. Chiron is named after the centaur Chiron in Greek mythology. It should not be confused with the largest moon of Pluto named Charon, discovered in 1978.
OrbitChiron's orbit was found to be highly eccentric, with perihelion just inside the orbit of Saturn and aphelion distance just outside the perihelion of Uranus (it does not reach the average distance of Uranus, however). Chiron's closest approach to Saturn in modern times was in May 720, at just under 30 Gm. It does not come nearly as close to Uranus; Chiron crosses Uranus' orbit where the latter is farther than average from the Sun. It attracted considerable interest because it was the first object discovered in such an orbit, well outside the asteroid belt. Chiron is now classified as a centaur, the first of a class of objects orbiting between the outer planets. Centaurs are not in stable orbits and will eventually be removed by gravitational perturbation by the giant planets, moving to different orbits or leaving the solar system altogether. Chiron is probably a refugee from the Kuiper belt. Physical characteristicsIn 1988 it was found that Chiron was undergoing an outburst in brightness (by about one magnitude), which is behaviour typical of comets but not asteroids. Further observations in 1989 showed that Chiron had developed a cometary coma. At the time of its discovery, Chiron was close to aphelion, whereas the observations showing a coma were done closer to perihelion, perhaps explaining why no cometary behavior had been seen earlier. Chiron is officially designated as both a comet and an asteroid, an indication of the sometimes fuzzy dividing line between the two classes of object. The term proto-comet has also been used. At approximately 180 km across, it is unusually large for a comet nucleus. Since the discovery of Chiron, quite a few other centaurs have been discovered, and nearly all are currently classified as asteroids but are being observed for possible cometary behavior. As of March 2006, only one has been observed to have a cometary coma: 60558 Echeclus, which now also has the cometary designation 174P/Echeclus. There are also three other non-centaur asteroids that are also classified as comets: 4015 Wilson-Harrington, 7968 Elst-Pizarro, and 118401 LINEAR. The centaur 60558 Echeclus is also cross-listed as comet 174P/Echeclus. References
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cs:2060 Chiron de:Chiron (Asteroid) et:2060 Chiron eo:Ĥirono (asteroido) fr:(2060) Chiron it:2060 Chiron he:כיירון (גוף במערכת השמש) ja:キロン (小惑星) pl:2060 Chiron sk:2060 Chiron tr:2060 Chiron | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
