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Astro*Dictionary by Michael Erlewine





5 articles for "Asteroids"

Asteroids [Astro*Index]

Low-mass, solid bodies, sometimes called planetoids or minor planets, gravitationally bound to the Sun and luminous with the Sun's light. The four largest are Ceres, Vesta, Pallas, and Juno. Chiron is most used by astrologers. Ceres is the largest, at 950 km diameter; the smallest are like boulders. Most asteroids orbit the Sun in a belt between Mars and Jupiter between 2.2 and 3.2 au. 4,000-odd asteroids have been formally numbered and named. The average eccentricity of their orbit is .15 and their average orbital inclination about 10°. There are millions of asteroids, most of them in a belt of such bodies orbiting between Mars and Jupiter. The outermost asteroid was thought to be Chiron with a 51-year orbital period until asteroid 1992AD was noted (on January 9, 1992 by David L. Rabinowitz) with a period 93 years, perihelion at approximately 8.7 au, aphelion at 32 au (extending far enough to cross the orbits of Saturn, Uranus, and Neptune), a maximum inclination to the ecliptic of 25°, and magnitude 17.


Name Size
  Orbital Period  
Mean distance
from Sun
to Ecliptic
Ceres380 km   4.60       2.766       .079       10.6°       9.08 hr  
Pallas240 km   4.61       2.768       .235       34.8°       10.0 hr  
Juno100 km   4.36       2.668       .256       13.0°       7.22 hr  
Vesta240 km   3.63       2.362       .088       7.1°       10.68 hr  
Chiron135 km   50.39       13.64       .381       6.9°       5.9 hr  


See also:
♦ Ceres ♦ Vesta ♦ Pallas ♦ Juno ♦ Chiron ♦ Perihelion ♦ Aphelion
Asteroids [Munkasey M.]

A body which is smaller than a planet and which has aregular Solar orbit. Asteroids are usually found in bands between the planets Mars and Jupiter.

See also:
♦ Ceres ♦ Vesta ♦ Pallas ♦ Juno ♦ Chiron ♦ Perihelion ♦ Aphelion
Asteroids [Prima]

The asteroid belt lies between the planets Mars and Jupiter in a large space where, according to the laws of astronomy, a planet ought to exist.

Theories abound as to the formation of the aster- oids. The most popular of these is that they are the remnants either of a planet that exploded or of a planet that was unable to form due to the tremendous gravitational influence of gigantic Jupiter. (The "Trojans," two large groups of asteroids, do in fact lie in Jupiter's orbit and revolve around the Sun as part of Jupiter's "entourage.")

Some of the asteroids have highly irregular orbits, passing even inside the orbit of Mercury at perihelion. There are literally thousands of these small bodies, ranging in size from less than a meter to several hundred kilometers in diameter. The first four were discovered between 1801 and 1807, and it was another 38 years before any others were discovered. These four, named after four Olympian goddesses, are being used by a growing number of astrologers and seem to symbolize various aspects of the Feminine:


Chiron has often been classified as an asteroid, even though it does not lie in the asteroid belt (orbiting primarily between Saturn and Uranus). It has also been called a comet, a planetoid, and a minor planet.

See also:
♦ Ceres ♦ Vesta ♦ Pallas ♦ Juno ♦ Chiron ♦ Perihelion ♦ Aphelion
Asteroids [DeVore]

v. Solar System.

See also:
♦ Solar System Bodies
Asteroid Belt [Astro*Index]

A belt or orbit containing a large number of minor planets midway between Mars and Jupiter.

See also:
♦ Ceres ♦ Vesta ♦ Pallas ♦ Juno ♦ Chiron ♦ Perihelion ♦ Aphelion


Astro*Index Copyright © 1997 Michael Erlewine