List of minor-planet groups

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A minor-planet group is a population of minor planets that 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 asteroid. It is customary to name a group of asteroids after the first member of that group to be discovered, which is often the largest.

Groups out to the orbit of Earth[]

There are relatively few asteroids that orbit close to the Sun. Several of these groups are hypothetical at this point in time, with no members having yet been discovered; as such, the names they have been given are provisional.

Groups out to the orbit of Mars[]

The asteroid belt[]

Histogram showing the four most prominent Kirkwood gaps and a possible division into inner, middle and outer main-belt asteroids:
  inner main-belt (a < 2.5 AU) ‹See Tfd›
  middle main-belt (2.5 AU < a > 2.82 AU) ‹See Tfd›
  outer main-belt (a > 2.82 AU ‹See Tfd›
Asteroid groups out to the orbit of Jupiter. The asteroid belt is shown in red

The overwhelming majority of known asteroids have orbits lying between the orbits of Mars and Jupiter, roughly between 2 and 4 AU. These could not form a planet due to the gravitational influence of Jupiter. Jupiter's gravitational influence, through orbital resonance, clears Kirkwood gaps in the asteroid belt, first recognised by Daniel Kirkwood in 1874.

The region with the densest concentration (lying between the Kirkwood gaps at 2.06 and 3.27 AU, with eccentricities below about 0.3, and inclinations smaller than 30°) is called the asteroid belt. It can be further subdivided by the Kirkwood Gaps into the:

Other groups out to the orbit of Jupiter[]

There are a number of more or less distinct asteroid groups outside the asteroid belt, distinguished either by mean distance from the Sun, or particular combinations of several orbital elements:

There is a forbidden zone between the Hildas and the Trojans (roughly 4.05 AU to 5.0 AU). Aside from 279 Thule and five objects in unstable-looking orbits, Jupiter's gravity has swept everything out of this region.

Groups beyond the orbit of Jupiter[]

Most of the minor planets beyond the orbit of Jupiter are believed to be composed of ices and other volatiles. Many are similar to comets, differing only in that the perihelia of their orbits are too distant from the Sun to produce a significant tail.

Groups at or beyond the orbit of Neptune[]

See also[]

References[]

  1. ^ "JPL Small-Body Database Search Engine: Q < 0.983 (AU)". JPL Solar System Dynamics. Retrieved 21 December 2017.
  2. ^ de la Fuente Marcos, C.; de la Fuente Marcos, R. (February 12, 2015). "Geometric characterization of the Arjuna orbital domain". Astronomische Nachrichten. 336 (1): 5–22. arXiv:1410.4104. Bibcode:2015AN....336....5D. doi:10.1002/asna.201412133.
  3. ^ Linda T. Elkins-Tanton – Asteroids, Meteorites, and Comets (2010) – Page 96 (Google Books)
  4. ^ Brož, M.; Vokrouhlický, D. (2008). "Asteroid families in the first-order resonances with Jupiter". Monthly Notices of the Royal Astronomical Society. 390 (2): 715–732. arXiv:1104.4004. Bibcode:2008MNRAS.390..715B. doi:10.1111/j.1365-2966.2008.13764.x.

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