Editing Solar System (section)

=== Kuiper belt ===
{{Main|Kuiper belt}}
[[File:Kuiper belt plot objects of outer solar system.png|right|thumb|Plot of objects around the [[Kuiper belt]] and other asteroid populations. J, S, U and N denotes Jupiter, Saturn, Uranus and Neptune.]]

[[File:TheKuiperBelt_classes-en.svg|thumb|Orbit classification of Kuiper belt objects. Some clusters that is subjected to [[orbital resonance]] are marked.]]
The Kuiper belt is a great ring of debris similar to the asteroid belt, but consisting mainly of objects composed primarily of ice.<ref name="physical">{{Cite book |last=Tegler |first=Stephen C. |url=https://archive.org/details/encyclopediasola00mcfa_702 |title=Encyclopedia of the Solar System |date=2007 |isbn=978-0120885893 |editor-last=Lucy-Ann McFadden |page=[https://archive.org/details/encyclopediasola00mcfa_702/page/n622 605]–620 |chapter=Kuiper Belt Objects: Physical Studies |display-editors=etal |url-access=limited}}</ref> It extends between 30 and 50&nbsp;AU from the Sun. It is composed mainly of small Solar System bodies, although the largest few are probably large enough to be dwarf planets.<ref name="Grundy2019">{{Cite journal |last1=Grundy |first1=W. M. |last2=Noll |first2=K. S. |last3=Buie |first3=M. W. |last4=Benecchi |first4=S. D. |last5=Ragozzine |first5=D. |last6=Roe |first6=H. G. |date=December 2018 |title=The Mutual Orbit, Mass, and Density of Transneptunian Binary Gǃkúnǁʼhòmdímà ({{Mp|(229762) 2007 UK|126}}) |url=http://www2.lowell.edu/~grundy/abstracts/2019.G-G.html |volume=334 |pages=30–38 |doi=10.1016/j.icarus.2018.12.037 |s2cid=126574999 |archive-url=https://web.archive.org/web/20190407045339/http://www2.lowell.edu/~grundy/abstracts/preprints/2019.G-G.pdf |archive-date=7 April 2019 |journal=Icarus|bibcode=2019Icar..334...30G }}</ref> There are estimated to be over 100,000 Kuiper belt objects with a diameter greater than {{Convert|50|km|abbr=on|sigfig=1}}, but the total mass of the Kuiper belt is thought to be only a tenth or even a hundredth the mass of Earth.<ref name="Delsanti-Beyond_The_Planets">{{Cite web |last1=Delsanti |first1=Audrey |last2=Jewitt |first2=David |date=2006 |title=The Solar System Beyond The Planets |url=http://www.ifa.hawaii.edu/faculty/jewitt/papers/2006/DJ06.pdf |url-status=dead |archive-url=https://web.archive.org/web/20070129151907/http://www.ifa.hawaii.edu/faculty/jewitt/papers/2006/DJ06.pdf |archive-date=29 January 2007 |access-date=3 January 2007 |website=Institute for Astronomy, University of Hawaii}}</ref> Many Kuiper belt objects have satellites,<ref>{{Cite journal |last1=Brown |first1=M.E. |author-link=Michael E. Brown |last2=Van Dam |first2=M.A. |last3=Bouchez |first3=A.H. |last4=Le Mignant |first4=D. |last5=Campbell |first5=R.D. |last6=Chin |first6=J.C.Y. |last7=Conrad |first7=A. |last8=Hartman |first8=S.K. |last9=Johansson |first9=E.M. |last10=Lafon |first10=R.E. |last11=Rabinowitz |first11=D.L. Rabinowitz |last12=Stomski |first12=P.J. Jr. |last13=Summers |first13=D.M. |last14=Trujillo |first14=C.A. |last15=Wizinowich |first15=P.L. |year=2006 |title=Satellites of the Largest Kuiper Belt Objects |url=http://web.gps.caltech.edu/~mbrown/papers/ps/gab.pdf |url-status=live |journal=[[The Astrophysical Journal]] |volume=639 |issue=1 |pages=L43–L46 |arxiv=astro-ph/0510029 |bibcode=2006ApJ...639L..43B |doi=10.1086/501524 |s2cid=2578831 |archive-url=https://web.archive.org/web/20180928185647/http://web.gps.caltech.edu/~mbrown/papers/ps/gab.pdf |archive-date=28 September 2018 |access-date=19 October 2011 |ref={{SfnRef|Brown Van Dam et al.|2006}}}}</ref> and most have orbits that are substantially inclined (~10°) to the plane of the ecliptic.<ref name="trojan">{{Cite journal |last1=Chiang |first1=E.I. |last2=Jordan |first2=A.B. |last3=Millis |first3=R.L. |last4=Buie |first4=M.W. |last5=Wasserman |first5=L.H. |last6=Elliot |first6=J.L. |last7=Kern |first7=S.D. |last8=Trilling |first8=D.E. |last9=Meech |first9=K.J. |last10=Wagner |first10=R.M. |display-authors=9 |date=2003 |title=Resonance Occupation in the Kuiper Belt: Case Examples of the 5:2 and Trojan Resonances |url=http://www.boulder.swri.edu/~buie/biblio/pub047.pdf |url-status=live |journal=[[The Astronomical Journal]] |volume=126 |issue=1 |pages=430–443 |arxiv=astro-ph/0301458 |bibcode=2003AJ....126..430C |doi=10.1086/375207 |s2cid=54079935 |archive-url=https://web.archive.org/web/20160315175243/http://www.boulder.swri.edu//~buie/biblio/pub047.pdf |archive-date=15 March 2016 |access-date=15 August 2009}}</ref>

The Kuiper belt can be roughly divided into the "[[Classical Kuiper belt object|classical]]" belt and the [[resonant trans-Neptunian object]]s.<ref name="physical" /> The latter have orbits whose periods are in a simple ratio to that of Neptune: for example, going around the Sun twice for every three times that Neptune does, or once for every two. The classical belt consists of objects having no resonance with Neptune, and extends from roughly 39.4 to 47.7&nbsp;AU.<ref>{{Cite journal |last1=Buie |first1=M. W. |last2=Millis |first2=R. L. |last3=Wasserman |first3=L. H. |last4=Elliot |first4=J. L. |last5=Kern |first5=S. D. |last6=Clancy |first6=K. B. |last7=Chiang |first7=E. I. |last8=Jordan |first8=A. B. |last9=Meech |first9=K. J. |last10=Wagner |first10=R. M. |last11=Trilling |first11=D. E. |date=2005 |title=Procedures, Resources and Selected Results of the Deep Ecliptic Survey |journal=[[Earth, Moon, and Planets]] |volume=92 |issue=1 |pages=113–124 |arxiv=astro-ph/0309251 |bibcode=2003EM&P...92..113B |doi=10.1023/B:MOON.0000031930.13823.be |s2cid=14820512}}</ref> Members of the classical Kuiper belt are sometimes called "cubewanos", after the first of their kind to be discovered, originally designated [[15760 Albion|1992 ''QB<sub>1</sub>'']], (and has since been named Albion); they are still in near primordial, low-eccentricity orbits.<ref>{{Cite journal |last1=Dotto |first1=E. |last2=Barucci |first2=M. A. |last3=Fulchignoni |first3=M. |date=1 January 2003 |title=Beyond Neptune, the new frontier of the Solar System |url=http://sait.oat.ts.astro.it/MSAIS/3/PDF/20.pdf |url-status=live |journal=Memorie della Societa Astronomica Italiana Supplementi |volume=3 |page=20 |bibcode=2003MSAIS...3...20D |issn=0037-8720 |archive-url=https://web.archive.org/web/20140825122005/http://sait.oat.ts.astro.it/MSAIS/3/PDF/20.pdf |archive-date=25 August 2014 |access-date=26 December 2006}}</ref>

There is strong consensus among astronomers that five members of the Kuiper belt are {{Visible anchor|Others|text=dwarf planets}}.<ref name="Grundy2019" /><ref name="JWST">{{cite journal |arxiv=2309.15230 |first1=J. P. |last1=Emery |first2=I. |last2=Wong |author-link= |title=A Tale of 3 Dwarf Planets: Ices and Organics on Sedna, Gonggong, and Quaoar from JWST Spectroscopy |date=2024 |first3=R. |last3=Brunetto |first4=J. C. |last4=Cook |first5=N. |last5=Pinilla-Alonso |first6=J. A. |last6=Stansberry |first7=B. J. |last7=Holler |first8=W. M. |last8=Grundy |first9=S. |last9=Protopapa |first10=A. C. |last10=Souza-Feliciano |first11=E. |last11=Fernández-Valenzuela |first12=J. I. |last12=Lunine |first13=D. C. |last13=Hines|journal=Icarus |volume=414 |doi=10.1016/j.icarus.2024.116017 |bibcode=2024Icar..41416017E }}</ref> Many dwarf planet candidates are being considered, pending further data for verification.<ref name="Tancredi2008">{{Cite journal |last1=Tancredi |first1=G. |last2=Favre |first2=S. A. |year=2008 |title=Which are the dwarfs in the Solar System? |journal=Icarus |volume=195 |issue=2 |pages=851–862 |bibcode=2008Icar..195..851T |doi=10.1016/j.icarus.2007.12.020}}</ref>
* {{Visible anchor|Pluto and Charon|text=[[Pluto]]}} (29.7–49.3&nbsp;AU) is the largest known object in the Kuiper belt. Pluto has a relatively eccentric orbit, inclined 17 degrees to the [[ecliptic plane]]. Pluto has a [[Orbital resonance|2:3 resonance]] with Neptune, meaning that Pluto orbits twice around the Sun for every three Neptunian orbits. Kuiper belt objects whose orbits share this resonance are called [[plutino]]s.<ref name="Fajans_et_al_2001">{{Cite journal |last1=Fajans |first1=J. |last2=Frièdland |first2=L. |date=October 2001 |title=Autoresonant (nonstationary) excitation of pendulums, Plutinos, plasmas, and other nonlinear oscillators |url=http://ist-socrates.berkeley.edu/~fajans/pub/pdffiles/AutoPendAJP.pdf |url-status=dead |journal=[[American Journal of Physics]] |volume=69 |issue=10 |pages=1096–1102 |bibcode=2001AmJPh..69.1096F |doi=10.1119/1.1389278 |archive-url=https://web.archive.org/web/20110607210435/http://ist-socrates.berkeley.edu/~fajans/pub/pdffiles/AutoPendAJP.pdf |archive-date=7 June 2011 |access-date=26 December 2006}}</ref> [[Moons of Pluto|Pluto has five moons]]: Charon, [[Styx (moon)|Styx]], [[Nix (moon)|Nix]], [[Kerberos (moon)|Kerberos]], and [[Hydra (moon)|Hydra]].<ref>{{Cite web |date=6 August 2021 |title=In Depth: Pluto |url=https://solarsystem.nasa.gov/planets/dwarf-planets/pluto/in-depth |url-status=live |archive-url=https://web.archive.org/web/20220331112026/https://solarsystem.nasa.gov/planets/dwarf-planets/pluto/in-depth |archive-date=31 March 2022 |access-date=31 March 2022 |website=NASA Science: Solar System Exploration}}</ref>
** [[Charon (moon)|Charon]], the largest of Pluto's moons, is sometimes described as part of a [[binary system (astronomy)|binary system]] with Pluto, as the two bodies orbit a [[barycenter]] of gravity above their surfaces (i.e. they appear to "orbit each other").
* {{Dp|Orcus}} (30.3–48.1&nbsp;AU), is in the same 2:3 orbital resonance with Neptune as Pluto, and is the largest such object after Pluto itself.<ref name="brownlargest" /> Its eccentricity and inclination are similar to Pluto's, but its perihelion lies about 120° from that of Pluto. Thus, the [[Phase (waves)#Phase difference|phase]] of Orcus's orbit is opposite to Pluto's: Orcus is at aphelion (most recently in 2019) around when Pluto is at perihelion (most recently in 1989) and vice versa.<ref name="MPC2004-D15">{{Cite web |date=20 February 2004 |title=MPEC 2004-D15 : 2004 DW |url=http://www.minorplanetcenter.net/mpec/K04/K04D15.html |url-status=live |archive-url=https://web.archive.org/web/20160303232947/http://www.minorplanetcenter.net/mpec/K04/K04D15.html |archive-date=3 March 2016 |access-date=5 July 2011 |publisher=Minor Planet Center}}</ref> For this reason, it has been called the ''anti-Pluto''.<ref name="MBP">{{Cite web |last=Michael E. Brown |author-link=Michael E. Brown |date=23 March 2009 |title=S/2005 (90482) 1 needs your help |url=http://www.mikebrownsplanets.com/2009/03/s1-90482-2005-needs-your-help.html |url-status=live |archive-url=https://web.archive.org/web/20090328012339/http://www.mikebrownsplanets.com/2009/03/s1-90482-2005-needs-your-help.html |archive-date=28 March 2009 |access-date=25 March 2009 |publisher=Mike Brown's Planets (blog)}}</ref><ref>{{Cite book |last=Moltenbrey |first=Michael |url=https://www.worldcat.org/oclc/926914921 |title=Dawn of Small Worlds: Dwarf planets, asteroids, comets |date=2016 |publisher=Springer |isbn=978-3-319-23003-0 |location=Cham |page=171 |oclc=926914921 |access-date=9 April 2022 |archive-url=https://web.archive.org/web/20220420161222/https://www.worldcat.org/title/dawn-of-small-worlds-dwarf-planets-asteroids-comets/oclc/926914921 |archive-date=20 April 2022 |url-status=live}}</ref> It has one known moon, [[Vanth (moon)|Vanth]].<ref name="IAUC8812">{{Cite web |last=Green |first=Daniel W. E. |date=22 February 2007 |title=IAUC 8812: Sats OF 2003 AZ_84, (50000), (55637), (90482) |url=http://www.cbat.eps.harvard.edu/iauc/08800/08812.html |url-status=live |archive-url=https://web.archive.org/web/20120314060043/http://cbat.eps.harvard.edu/iauc/08800/08812.html |archive-date=14 March 2012 |access-date=4 July 2011 |publisher=International Astronomical Union Circular}}</ref>
* [[Haumea]] (34.6–51.6&nbsp;AU) was discovered in 2005.<ref>{{Cite web |date=17 September 2008 |title=IAU names fifth dwarf planet Haumea |url=https://www.iau.org/news/pressreleases/detail/iau0807 |url-status=live |archive-url=https://web.archive.org/web/20140425065601/http://iau.org/public_press/news/detail/iau0807 |archive-date=25 April 2014 |access-date=9 April 2022 |website=International Astronomical Union}}</ref> It is in a temporary 7:12 orbital resonance with Neptune.<ref name="brownlargest">{{Cite book |last=Brown |first=Mike |title=The Solar System Beyond Neptune |publisher=University of Arizona Press |year=2008 |isbn=978-0-816-52755-7 |editor-last=Barucci |editor-first=M. Antonietta |pages=335–344 |chapter=The largest Kuiper belt objects |oclc=1063456240 |author-link=Mike Brown (astronomer) |access-date=9 April 2022 |chapter-url=http://www.gps.caltech.edu/~mbrown/papers/ps/kbochap.pdf |archive-url=https://web.archive.org/web/20121113114533/http://www.gps.caltech.edu/~mbrown/papers/ps/kbochap.pdf |archive-date=13 November 2012 |url-status=live}}</ref> Haumea possesses a ring system, two known moons named [[Hiʻiaka (moon)|Hiʻiaka]] and [[Namaka (moon)|Namaka]], and rotates so quickly (once every 3.9 hours) that it is stretched into an [[ellipsoid]]. It is part of a [[collisional family]] of Kuiper belt objects that share similar orbits, which suggests a giant impact on Haumea ejected fragments into space billions of years ago.<ref name="Noviello2022">{{Cite journal |last1=Noviello |first1=Jessica L. |last2=Desch |first2=Stephen J. |last3=Neveu |first3=Marc |last4=Proudfoot |first4=Benjamin C. N. |last5=Sonnett |first5=Sarah |date=September 2022 |title=Let It Go: Geophysically Driven Ejection of the Haumea Family Members |journal=The Planetary Science Journal |volume=3 |issue=9 |page=19 |bibcode=2022PSJ.....3..225N |doi=10.3847/PSJ/ac8e03 |s2cid=252620869 |id=225 |doi-access=free}}</ref>
* [[Makemake]] (38.1–52.8&nbsp;AU), although smaller than Pluto, is the largest known object in the ''classical'' Kuiper belt (that is, a Kuiper belt object not in a confirmed resonance with Neptune). Makemake is the brightest object in the Kuiper belt after Pluto. Discovered in 2005, it was officially named in 2009.<ref>{{Cite web |date=19 July 2009 |title=Fourth dwarf planet named Makemake |url=https://www.iau.org/news/pressreleases/detail/iau0806 |url-status=live |archive-url=https://web.archive.org/web/20170730222925/https://www.iau.org/news/pressreleases/detail/iau0806 |archive-date=30 July 2017 |access-date=9 April 2022 |website=International Astronomical Union}}</ref> Its orbit is far more inclined than Pluto's, at 29°.<ref name="Buie136472">{{Cite web |last=Buie |first=Marc W. |author-link=Marc W. Buie |date=5 April 2008 |title=Orbit Fit and Astrometric record for 136472 |url=http://www.boulder.swri.edu/~buie/kbo/astrom/136472.html |url-status=live |archive-url=https://web.archive.org/web/20200527191044/https://www.boulder.swri.edu/~buie/kbo/astrom/136472.html |archive-date=27 May 2020 |access-date=15 July 2012 |publisher=SwRI (Space Science Department)}}</ref> It has one known moon, [[S/2015 (136472) 1]].<ref name="ParkerA2016">{{Cite journal |last1=Parker |first1=A. H. |last2=Buie |first2=M. W. |last3=Grundy |first3=W. M. |last4=Noll |first4=K. S. |date=25 April 2016 |title=Discovery of a Makemakean Moon |journal=[[The Astrophysical Journal]] |volume=825 |issue=1 |page=L9 |arxiv=1604.07461 |bibcode=2016ApJ...825L...9P |doi=10.3847/2041-8205/825/1/L9 |s2cid=119270442 |doi-access=free}}</ref>
* {{Dp|Quaoar}} (41.9–45.5&nbsp;AU) is the second-largest known object in the classical Kuiper belt, after Makemake. Its orbit is significantly less eccentric and inclined than those of Makemake or Haumea.<ref name="brownlargest" /> It possesses a ring system and one known moon, [[Weywot (moon)|Weywot]].<ref name="Morgado2023">{{Cite Q|Q116754015|display-authors=1}}</ref>