The Collaborative International Dictionary of English. 2000.
perihelia — per·i·he·li·on || ‚perɪ hɪËlɪən n. closest point to the sun in the orbit of a planet or comet … English contemporary dictionary
Groups of minor planets — An asteroid group or minor planet group is a population of minor planets that have a share broadly similar orbits. Members are generally unrelated to each other, unlike in an asteroid family, which often results from the break up of a single… … Wikipedia
List of Mercury-crossing minor planets — A Mercury crosser is an asteroid whose orbit crosses that of Mercury. The Mercury crossers proper have aphelia outside Mercury s (0.4667 AU) and perihelia inside Mercury s (0.3075 AU), while those listed here as outer grazers have perihelia… … Wikipedia
comet — cometary /kom i ter ee/, cometic /keuh met ik/, cometical, adj. cometlike, adj. /kom it/, n. Astron. a celestial body moving about the sun, usually in a highly eccentric orbit, consisting of a central mass surrounded by an envelope of dust and… … Universalium
Near-Earth asteroid — Near Earth asteroids (NEAs) are asteroids whose orbits are close to Earth s orbit. All near Earth asteroids spend part of their orbits between 0.983 and 1.3 astronomical units away from the Sun. Some near Earth asteroids orbits intersect Earth s… … Wikipedia
Near-Earth object — Asteroid 4179 Toutatis is a potentially hazardous object that has passed within 2.3 lunar distances … Wikipedia
Oort cloud — An artist s rendering of the Oort cloud and the Kuiper belt (inset). Sizes of individual objects have been exaggerated for visibility … Wikipedia
Centaur (minor planet) — The centaurs are an unstable orbital class of minor planets named after the mythological race of centaurs. The name was chosen because they behave as half asteroid and half comet. Centaurs have transient orbits that cross or have crossed those of … Wikipedia
90482 Orcus — Discovery[1] Discovered by M. Brown, C. Trujillo, D … Wikipedia
List of Mercury-crossing asteroids — A Mercury crosser asteroid is an asteroid whose orbit crosses that of Mercury. The Mercury crossers proper have aphelia outside Mercury s and perihelia inside, while those listed here as outer grazers have perihelia within Mercury s aphelion but… … Wikipedia
