Known Space -- Sol -- | Asteroids |
There are some 40,000 large asteroids within the Solar system. Many (but not all) lie in a vague band between Mars and Jupiter ... sometimes called the Asteroid Belt. To list all of them here would be impractical, so here are the largest:
Asteroid Distance Year Day Diameter Ceres 2.66 AU 4.60 yr 0.378 d 0.074 Vesta 2.26 AU 3.63 yr 0.223 d 0.045 Pallas 2.45 AU 4.62 yr 0.325 d 0.041 Hygeia 2.95 AU 5.54 yr 0.729 d 0.034 Davida 2.90 AU 5.66 yr 0.217 d 0.030 Interamnia 2.84 AU 5.36 yr 0.363 d 0.026 Cybele 3.25 AU 6.36 yr 0.254 d 0.024 Europa 3.04 AU 5.48 yr 0.233 d 0.023 Sylvia 3.34 AU 6.50 yr 0.217 d 0.022 Patientia 2.96 AU 5.36 yr 0.404 d 0.022 Euphrosyne 2.79 AU 5.58 yr 0.230 d 0.021 Eunomia 2.40 AU 4.30 yr 0.253 d 0.020 Bamberga 2.23 AU 4.39 yr 1.225 d 0.020 Psyche 2.73 AU 5.00 yr 0.175 d 0.019 Juno 2.33 AU 4.36 yr 0.300 d 0.018 |
As was stated above the Asteroid Belt is a vaguely defined region. Many asteroids have highly eccentric orbits that actually cross those of other planets. Aten asteroids are those that have an average distance from the sun of less than 1 AU which MAY cross the Earth's orbit (the largest is 1986-TO with a diameter of 3 km). Apollo asteroids have an average distance from the sun of more than 1 AU but cross the Earth's orbit (the largest is Hephaistos with a diameter of 8.8 km). Amor asteroids cross the orbit of Mars but not the orbit of Earth (the largest is Ganymed with a diameter of 40 km).
In addition to the main concentration a second, mini-belt, lies roughly between 35 AU and 45 AU from the sun. This is called the Kuiper Belt. Some astronomers classify Pluto itself as a Kuiper Belt object. The six largest Kuiper Belt objects (not including Pluto) are:
Asteroid Distance Year Diameter 1993-SC 39.5 AU 248.2 yr 0.025 1992-QB 43.9 AU 290.2 yr 0.022 1993-FW 43.9 AU 291.2 yr 0.020 Chiron 13.5 AU 50.7 yr 0.016 Pholus 20.4 AU 93.0 yr 0.016 1993-SB 39.4 AU 247.5 yr 0.015 |
Many asteroids are not is stable orbits. Eros, an Amor type asteroid with a diameter of 22 km, is due to strike the Earth in about 100,000 years from now. However, since a lot of the smaller asteroids remain unclassified, and sometimes even undetected, the risk of an Earth-strike in the near future remains ever present.