Kuiper Belt - Agreed Terms


"Science begets knowledge, opinion ignorance.
Kuiper Belt – Agreed Terms

Comets, Meteors and Asteroids” by John Man BBC 2001

“Kuiper Belt

This belt of icy bodies is named after the Dutch-American astronomer Gerard Kuiper, who suggested its existence in 1951. The suggestion became more attractive in 1980, when Julio Fernandez of the National Astronomy Observatory, Madrid, pointed out that most short-period comets orbited in the same plane as the planets, and ought therefore to have their origins in an extension of the disc of dust and gas from which the planets had condensed. For a few years, this remained a theory. Then in the mid 1980s, USA’s Infrared Astronomical Sattelite (IRAS) photographed such a belt around a star in the constellation Pictor. Then, in 1992, David Jewitt and Jane Luu at the University of Hawaii spotted a tiny object, about 320 km (200 miles) across, orbiting beyond Neptune – the first Kuiper Belt Object (KBO).

Uranus, Neptune, Pluto and the Outer Solar System” by Linda T Elkins-Tanton Chelsea House 2006

Kuiper Belt and Kuiper Belt Objects

“Neptune’s orbit carries the planet from 29.8 to 30.3 AU from the Sun. Small bodies orbiting past Neptune are referred to as trans-Neptunian objects, and then are further sub-divided into members of the Kuiper Belt or the Oort Cloud. Neptune marks the inner edge of the Kuiper Belt. The Kuiper Belt was originally thought to reach from 35 to 100 AU from the Sun, and then to merge into the Oort Cloud of icy bodies. . . . . . . there (now) appears to be a gap between the edge of the Kuiper Belt and the beginning of the comet-rich Oort Cloud. The Kuiper Belt begins around 30 AU and has a sharp outer edge at 49 AU.” . . . . . . . . .

“The Kuiper Belt had been postulated since 1943, but it remained a theory until 1992. Only the development of a highly sensitive viewing instrument, called a charge-couple device has allowed astronomers to see the tiny bodies in the Kuiper Belt.” . . . . . . . . .

Kuiper Belt Bodies are divided into three classes according to their orbits; classical (or cubewano), resonance (or plutino), or scattered disk (object). Classical Kuiper Belt Objects have orbits with low eccentricity and low inclination, indicating that they formed from the solar nebula in place and have not been further perturbed. These objects are sometimes called cubewanos and include any large KBO orbiting between about 41 and 48 AU but not controlled by orbital resonances with Neptune. The name is derived from 1992 QB1, the first KBO found. Subsequent objects were called “que-be-one-os”, or cubewanos. There are about 524 cubewanos known as of 2004. Resonance Kuiper Belt Objects are protected from gravitational perturbation by integral ratios between their orbital periods and Neptune’s. Like Pluto, many KBOs have orbits in periods of 3:2 with Neptune. . . . Because they share their resonance with Pluto, they are called plutinos. As of 2005, there were about 150 plutinos and 22 other resonance objects.” . . . . .

“The third class, scattered disk (Kuiper Belt) objects, have large, eccentric orbits, perhaps created by gravitational interactions with the giant planets. There are about 100 known (2006) scattered disk objects. The KBO 1996TL66 is a good example of this class, with an orbital eccentricity of 0.59 that carries it to 130 AU at aphelion. There are thought to be as many as 10,000 scattered disk objects.”

Comets Visitors from Deep Space” by David J Eicher Cambridge University Press 2013

Kuiper Belt

A region of small Solar System bodies beyond the planets, extending from the orbit of Neptune (at about 30 AU from the Sun) to approximately 50 AU from the Sun. Named for Dutch American astronomer Gerard P Kuiper.

“Fundamental Planetary Science” by Jack Lissauer and Imke de Pater CUP 2019

“Kuiper Belt

The Kuiper Belt is a thick disk of ice/rock bodies beyond the orbit of Neptune. The two largest members of the Kuiper Belt to have been sighted are Eris, whose heliocentric distance oscillates between 38 and 97 AU, and Pluto, whose heliocentric distance varies from 29 to 50 AU. The radii of Eris and Pluto exceed 1000 km.”

Kuiper Belt Objects

Kuiper Belt Objects (KBOs) are icy bodies, and the largest KBOs are an order of magnitude more massive than 1 Ceres. The total mass of the Kuiper Belt exceeds that of the Asteroid Belt by about two orders of magnitude. Yet, because the Kuiper Belt is located much further from both the Earth and the Sun than the Asteroid Belt, more is known about asteroids than about KBOs.”

“The Kuiper Belt is also the primary source of the Short Period or Ecliptic Comets (ECs), comets that are on eccentric orbits near the ecliptic plane and return with regularity (orbital periods <200 years) to the inner Solar System.” See Oort Cloud for long-period comets (>~ 10,000 AU

Work in progress Last edit 11th October 2021 11.15 BST..
Last edited:


"Science begets knowledge, opinion ignorance.
Encyclopaedia of the Solar System” Academic Press Ed Weissman, McFadden and Johnson.

A mammoth book of over 1000 pages. The Kuiper Belt chapter takes up 26 pages, with a further 20 pages devoted to Pluto and Charon.

From Historical Perspective:

“The planets formed in a disk of material that originally surrounded the Sun. . . . . . . . . . Then there is Pluto, unique, having an orbital inclination of 15.6o . . . . . . . . . having an orbit that crosses the orbit of … Neptune. So, the historical view was that Pluto was an oddity in the Solar System. . . . This view, however, changed in September 1992 with the announcement of the discovery of the first of a population of small (compared to planetary bodies) objects orbiting beyond the orbit of Neptune, in the same region as Pluto. Since that time, 60 objects with radii between about 50 and 500 km have been discovered. . . . There are almost certainly very more smaller ones. . . . “

“The discovery of the Kuiper Belt, as it has come to be known, represents a revolution in our thinking about the Solar System. First predicted on theoretical grounds and later confirmed by observations, the Kuiper Belt is the first totally new class of bodies to be discovered in the Solar System since the first asteroid was found on New Year’s Day in 1801. . . . . . . “

“However, the idea was resurrected in 1980 when Julio Fernandez proposed that a cometary disk beyond Neptune could be a possible source reservoir for the short-period comets (those with orbital periods < 200 years). Subsequent dynamical simulations showed that a comet belt beyond Neptune is the most plausible source for the low inclination, Jupiter-family comets. This work led observers to search for Kuiper Belt objects, the first one being discovered by David Jewitt and Jane Luu in August 1992. Since then, over 60 KBOs with estimated radii >~50 km (assuming a typical cometary nucleus albedo pf 0.04) have been found by ground based searches, and about 30 comet-sized (radii <~10 km) objects have been detected using the Hubble Space Telescope. (Because the Kuiper Belt is believed to be the source of the Jupiter-family short-period comets, typical cometary albedos of 4% are assumed for the surfaces of KBOs.)”

“Two populations of objects in the Solar System are related to the Kuiper Belt. The first consists of a large number (~106) of (presumably) icy objects on planet-crossing orbits interior to Neptune’s orbit. These objects are known as ecliptic comets and they most likely originated in the Kuiper Belt. Ecliptic comets include two distinct subpopulations: Centaurs and Jupiter-family comets. Known Centaurs are 20- to 100- km-radius objects with semi-major axes beyond the orbit of Jupiter, most of which appear to be inactive (a notable exception is the first Centaur discovered, 2060 Chiron). Jupiter-family comets are much smaller objects a few kilometers in diameter on Jupiter-crossing orbits but with semimajor axes interior to Jupiter. Most of the known Jupiter-family comets are active comets, as active comets are much brighter and hence easier to detect than inactive ones.” . . . . . . . . .

“The second related population of objects is known as the scattered comet disk. (Discovered in) 1996, the scattered disk occupies the same volume of physical space as the Kuiper Belt, but has a different dynamical character and a different origin.” . . . . . . . . .

“It is rare in the history of astronomy that a whole new region of the Solar System is discovered that needs to be understood. . . . . . . . . . The discovery of duct disks around nearby stars by the IRAS satellite in 1983-4 suggests that Kuiper Belts may be a natural consequence of star and planet formation, thus providing us with a tool for studying solar system formation around other stars.”
Last edited:
  • Like
Reactions: sam85geo