Kuiper belt

"KBOs" redirects here. For other uses, see KBOS (disambiguation).

Known objects in the Kuiper belt beyond the orbit of Neptune. (Scale in AU; epoch as of January 2015.)
  Sun
  Jupiter trojans
  Giant planets:

  Centaurs 		  Neptune trojans
  Resonant Kuiper belt
  Classical Kuiper belt
  Scattered disc
Distances but not sizes are to scale. The yellow disk is about the size of Mars' orbit.
Source: Minor Planet Center, www.cfeps.net and others
Types of distant minor planets

The Kuiper belt (/ˈkaɪpər/ KY-pər)[1] is a circumstellar disc in the outer Solar System, extending from the orbit of Neptune at 30 astronomical units (AU) to approximately 50 AU from the Sun.[2] It is similar to the asteroid belt, but is far larger—20 times as wide and 20–200 times as massive.[3][4] Like the asteroid belt, it consists mainly of small bodies or remnants from when the Solar System formed. While many asteroids are composed primarily of rock and metal, most Kuiper belt objects are composed largely of frozen volatiles (termed "ices"), such as methane, ammonia, and water. The Kuiper belt is home to most of the objects that astronomers generally accept as dwarf planets: Orcus, Pluto,[5] Haumea,[6] Quaoar, and Makemake.[7] Some of the Solar System's moons, such as Neptune's Triton and Saturn's Phoebe, may have originated in the region.[8][9]

The Kuiper belt is named in honor of the Dutch astronomer Gerard Kuiper, who conjectured the existence of the belt in 1951.[10] There were researchers before and after him who also speculated on its existence, such as Kenneth Edgeworth in the 1930s.[11] The astronomer Julio Angel Fernandez published a paper in 1980 suggesting the existence of a comet belt beyond Neptune[12][13] which could serve as a source for short-period comets.[14][15]

In 1992, minor planet (15760) Albion was discovered, the first Kuiper belt object (KBO) since Pluto (in 1930) and Charon (in 1978).[16] Since its discovery, the number of known KBOs has increased to thousands, and more than 100,000 KBOs over 100 km (62 mi) in diameter are thought to exist.[17] The Kuiper belt was initially thought to be the main repository for periodic comets, those with orbits lasting less than 200 years. Studies since the mid-1990s have shown that the belt is dynamically stable and that comets' true place of origin is the scattered disc, a dynamically active zone created by the outward motion of Neptune 4.5 billion years ago;[18] scattered disc objects such as Eris have extremely eccentric orbits that take them as far as 100 AU from the Sun.[a]

The Kuiper belt is distinct from the hypothesized Oort cloud, which is believed to be a thousand times more distant and mostly spherical. The objects within the Kuiper belt, together with the members of the scattered disc and any potential Hills cloud or Oort cloud objects, are collectively referred to as trans-Neptunian objects (TNOs).[21] Pluto is the largest and most massive member of the Kuiper belt and the largest and the second-most-massive known TNO, surpassed only by Eris in the scattered disc.[a] Originally considered a planet, Pluto's status as part of the Kuiper belt caused it to be reclassified as a dwarf planet in 2006. It is compositionally similar to many other objects of the Kuiper belt, and its orbital period is characteristic of a class of KBOs, known as "plutinos," that share the same 2:3 resonance with Neptune.

The Kuiper belt and Neptune may be treated as a marker of the extent of the Solar System, alternatives being the heliopause and the distance at which the Sun's gravitational influence is matched by that of other stars (estimated to be between 50000 AU and 125000 AU).[22]

  1. ^ "Kuiper belt". Lexico UK English Dictionary. Oxford University Press. Archived from the original on 26 November 2021.
  2. ^ Stern, Alan; Colwell, Joshua E. (1997). "Collisional erosion in the primordial Edgeworth-Kuiper belt and the generation of the 30–50 AU Kuiper gap". The Astrophysical Journal. 490 (2): 879–882. Bibcode:1997ApJ...490..879S. doi:10.1086/304912.
  3. ^ Delsanti, Audrey & Jewitt, David (2006). The Solar System beyond the Planets (PDF). Institute for Astronomy. University of Hawaii. Bibcode:2006ssu..book..267D. Archived from the original (PDF) on 25 September 2007. Retrieved 9 March 2007.
  4. ^ Krasinsky, G. A.; Pitjeva, E. V.; Vasilyev, M.V.; Yagudina, E.I. (July 2002). "Hidden Mass in the Asteroid Belt". Icarus. 158 (1): 98–105. Bibcode:2002Icar..158...98K. doi:10.1006/icar.2002.6837.
  5. ^ Christensen, Lars Lindberg. "IAU 2006 General Assembly: Result of the IAU Resolution votes". IAU. Archived from the original on 29 April 2014. Retrieved 25 May 2021.
  6. ^ Christensen, Lars Lindberg. "IAU names fifth dwarf planet Haumea". IAU. Archived from the original on 25 April 2014. Retrieved 25 May 2021.
  7. ^ Christensen, Lars Lindberg. "Fourth dwarf planet named Makemake". IAU. Archived from the original on 16 June 2019. Retrieved 25 May 2021.
  8. ^ Johnson, Torrence V.; and Lunine, Jonathan I.; Saturn's moon Phoebe as a captured body from the outer Solar System, Nature, Vol. 435, pp. 69–71
  9. ^ Craig B. Agnor & Douglas P. Hamilton (2006). "Neptune's capture of its moon Triton in a binary-planet gravitational encounter" (PDF). Nature. 441 (7090): 192–4. Bibcode:2006Natur.441..192A. doi:10.1038/nature04792. PMID 16688170. S2CID 4420518. Archived from the original (PDF) on 21 June 2007. Retrieved 20 June 2006.
  10. ^ Kuiper, G.P. (1951). "On the origin of the solar system". In Hynek, J.A. (ed.). Astrophysics: A Topical Symposium. New York City, New York, US: McGraw-Hill. pp. 357–424.
  11. ^ "Kuiper Belt: Facts - NASA Science".
  12. ^ JA Fernandez (1980). "On the existence of a comet belt beyond Neptune". Observatorio Astronomico Nacional, Madrid. 192 (3): 481–491. Bibcode:1980MNRAS.192..481F. doi:10.1093/mnras/192.3.481.
  13. ^ Morbidelli, A.; Thomas, F.; Moons, M. (1 December 1995). "The Resonant Structure of the Kuiper Belt and the Dynamics of the First Five Trans-Neptunian Objects". Icarus. 118 (2): 322–340. Bibcode:1995Icar..118..322M. doi:10.1006/icar.1995.1194. ISSN 0019-1035.
  14. ^ gunjan.sogani (10 September 2022). "The Discovery of the Kuiper Belt and Its Members". Wondrium Daily. Archived from the original on 1 August 2023. Retrieved 1 August 2023.
  15. ^ "Julio A. Fernández". nationalacademyofsciences.org. Archived from the original on 1 August 2023. Retrieved 1 August 2023.
  16. ^ Cite error: The named reference qbee was invoked but never defined (see the help page).
  17. ^ "The PI's Perspective". New Horizons. 24 August 2012. Archived from the original on 13 November 2014.
  18. ^ Levison, Harold F.; Donnes, Luke (2007). "Comet Populations and Cometary Dynamics". In Lucy Ann Adams McFadden; Paul Robert Weissman; Torrence V. Johnson (eds.). Encyclopedia of the Solar System (2nd ed.). Amsterdam; Boston: Academic Press. pp. 575–588. ISBN 978-0-12-088589-3.
  19. ^ Weissman and Johnson, 2007, Encyclopedia of the solar system, footnote p. 584
  20. ^ IAU: Minor Planet Center (3 January 2011). "List Of Centaurs and Scattered-Disk Objects". Central Bureau for Astronomical Telegrams, Harvard-Smithsonian Center for Astrophysics. Archived from the original on 29 June 2017. Retrieved 3 January 2011.
  21. ^ Gérard FAURE (2004). "Description of the System of Asteroids as of May 20, 2004". Archived from the original on 29 May 2007. Retrieved 1 June 2007.
  22. ^ "Where is the Edge of the Solar System?". Goddard Media Studios. NASA's Goddard Space Flight Center. 5 September 2017. Archived from the original on 16 December 2021. Retrieved 22 September 2019.


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