Centaur
In Astronomy a centaur is an atypical asteroid, with an atypical orbit, between those of Planet Jupiter and Planet Neptune.[1] Centaurs are also atypical in that they leave a coma -- a tail, like a comet.
Centaurs are believed to be misplaced Kuiper Belt objects, that entered the region of the Solar system's outter planets after an orbit where they passed too close to Neptune.[1]
Astronomers believe that, since their orbits cross those of the outer planets they are not, ultimately stable, and that Centaurs' orbits are likely to be further perturbed, so that they are deflected to come closer to Sol, our sun, like real comets', or to be cast out of the Solar system, altogether.
2060 Chiron, the first of the class to be found, was discovered in 1977.[1] And, since that asteroid's name was that of a Centaur, from Greek mythology, the whole class ended up being called Centaurs.
| name | discovered | diameter | notes |
|---|---|---|---|
| 2060 Chiron | 1977 |
| |
| 5145 Pholus | 1992-01-09 | 190 kilometres (120 mi) | |
| 10199 Chariklo | |||
| 8405 Asbolus | |||
| 7066 Nessus | |||
| 944 Hidalgo | 1920-10-31 | 38 kilometres (24 mi) |
|
| 31824 Elatus |
References
[edit | edit source]- ↑ 1.0 1.1 1.2 1.3
Tom Metcalfe (2021-10-07). "Our solar system's centaurs are half-asteroid, half-comet". Astronomy Magazine. Archived from the original on 2025-03-16. Retrieved 2026-07-12.
Centaurs are among the strangest objects in the solar system. The first, dubbed Chiron, was spotted orbiting more than a billion miles from the Sun in 1977 and was originally thought to be an asteroid. But a few years later it was seen emitting a halo of gas — a “coma” — and a tail like a comet.
- ↑
M.C. De Sanctis; M.T. Capria; A. Coradini; R. Orosei (September 2000). "Thermal Evolution of the Centaur Object 5145 Pholus". The Astronomical Journal. 120 (3): 1571-1578. doi:10.1086/301512. Archived from the original on 2023-11-24. Retrieved 2026-07-12.
The most likely source of Centaurs is the Edgeworth-Kuiper belt: dynamical studies and physical properties suggest that Pholus recently entered the planetary zone.
- ↑
D. P. Cruikshank; T. L. Roush; M. J. Bartholomew; T. R. Geballe; Y. J. Pendleton; S. M. White; J. F. Bell, III; J. K. Davies; T. C. Owen; C. de Bergh; D. J. Tholen; M. P. Bernstein; R. H. Brown; K. A. Tryka; C. M. Dalle Ore (1999-04-29). "The Composition of Centaur 5145 Pholus" (PDF). Icarus (journal). 135: 389–407. Archived from the original (PDF) on 2025-09-14. Retrieved 2026-07-12.
While the orbit of Pholus is comet-like, its dimensions are an order of magnitude greater than those of a typical comet nucleus and are more similar to many asteroids
- ↑
"Asteroid Hidalgo". Space Reference. Archived from the original on 2025-12-17. Retrieved 2026-07-12.
Hidalgo orbits the sun every 5,010 days (13.72 years), coming as close as 1.94 AU and reaching as far as 9.52 AU from the sun. Hidalgo is about 38.0 kilometers in diameter, making it larger than 99% of asteroids, comparable in size to the city of Houston.