asteroid belt

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asteroid belt

(main belt) The zone near to the plane of the ecliptic and between the orbits of Mars and Jupiter that contains the majority of asteroids, known as main-belt asteroids. The edges are well-defined at distances from the Sun of about 1.7 and 4.0 AU respectively and the orbits are strongly concentrated in the plane of the ecliptic. Even so, the individual asteroids in the main belt are widely spaced. The orbital inclination becomes more scattered on moving through the belt. The average inclination is about 10° and the average eccentricity is 0.15. All the bodies are in direct motion. Occasional collisions between asteroids occur at velocities of about 5 km s–1. See also Kirkwood gaps.

asteroid belt

[′as·tə‚rȯid ‚belt]
(astronomy)
The region between 2.1 and 3.5 astronomical units from the sun where most of the asteroids are found.