
Pluto, minor planet designation (134340) Pluto is the second closest dwarf planet to the Sun, formerly known as the ninth planet. It was discovered on February 18, 1930 by astronomer Clyde W. Tombaugh. It is the largest object in the Kuiper belt but less dense than Eris. It was originally referred to as the ninth planet, but was demoted into being classified as a dwarf planet in 2006.
Pluto's natural satellite, Charon, is half the size of Pluto. In fact, it is so big that Pluto orbits Charon too. But the IAU has yet to formalize a definition for a binary dwarf planet system, so Charon is classified as a satellite for now.
Moons
Main article: Moons of Pluto
Pluto has 5 natural satellites. Charon, Nix, Kerberos, Hydra, and Styx. Charon is half of Pluto's diameter.
Interior

Interior of Pluto (model 1)
The outer crust of Pluto is made of frozen nitrogen and water ice. Under the crust is either a frozen layer of water or liquid water. The final layer is the middle of Pluto, a silicate core.
Formation
Pluto was formed from a clump of rocky materials and particles around 4.5 billion years ago between the location of Neptune and Uranus.
It propelled to the edge of the Solar System during the Migration of Neptune event as Jupiter's and Saturn's gravity propelled Neptune towards the edge of the Solar System.
Surface
Not much is known about Pluto's surface.
Scientists theorize hydrocarbon atoms form when the Sun's light rays hit Pluto's surface, which could explain why Pluto's snow looks a bit reddish-brown. However, artist depictions describe Pluto's surface as being a bumpy place being made of rock. Pluto has numerous caverns and mountainous areas.
Atmosphere

Atmosphere of Pluto, taken by New Horizons.
Pluto does not have a significant atmosphere. It has a thin envelope of gas that is most likely made up of nitrogen, methane, and carbon monoxide, that develops in equilibrium with solid nitrogen and carbon monoxide ices on the surface as it approaches the Sun. As Pluto moves away from its perihelion (closest point to the Sun), more of its atmosphere freezes and falls to the ground. When it returns to a closer proximity to the Sun, the temperature of Pluto's solid surface will increase, causing the nitrogen ice to sublimate into gas—creating an anti-greenhouse effect. Much as sweat evaporating from the surface of human skin, this sublimation has a cooling effect and scientists have recently discovered, by use of the sub-millimeter array, that Pluto's temperature is 10 kelvin less than they expected.
Gallery

The Planets and Dwarf Planets | |
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Planets | |
Inner: (Mercury • Venus • Earth • Mars) Outer: (Jupiter • Saturn • Uranus • Neptune) | |
Dwarf Planets (and candidates) | |
Ceres • Pluto • Haumea • Makemake • Quaoar • Orcus • Eris • Gonggong • Sedna |
Geology of Pluto | |
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Regions | Belton • Tombaugh "The Heart" • Lowell |
Terrae | Hayabusa • Pioneer • Venera • Viking • Voyager |
Maculae | "Brass Knuckles" (Krun • Ala • Balrog • Vucub-Came • Hun-Came • Meng-pʻo) • Cadejo • Morgoth |
Hills and Mountains | Challenger Colles • Coleta de Dados Colles • Hillary Montes • Tenzing Montes |
Plains | Sputnik Planitia |
Valleys and Depressions | Quidlivun Cavus |
Lineaea | Luna Linea |
Craters | Bower • Burney • Brinton • Coradini • Coughlin • Edgeworth |
Dwarf Planets, Dwarf Planet Candidates and large Trans-Neptunian Objects | ||
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Consensus | Ceres • Orcus • Pluto • Haumea • Makemake • Quaoar • Eris • Gonggong • Sedna | |
Candidate D > 300 km or H <6.0 |
Asteroids | |
Centaurs | ||
Plutinos | Huya • Ixion • Lempo • 1993 SC • 1998 VG₄₄ • 2000 GP₁₈₃ • 2001 QF₂₉₈ • 2001 XD₂₅₅ • • 2002 VR₁₂₈ • • 2002 XV₉₃ • 2003 AZ₈₄ • 2003 QX₁₁₁ • 2003 UZ₄₁₃ • 2003 VS₂ • 2005 GW₁₈₆ • 2007 JF₄₃ • 2007 JH₄₃ • 2007 JF₄₅ • 2010 EL₁₃₉ • 2011 UT₄₁₀ • 2011 VJ₂₄ • 2013 CD₂₂₃ • 2013 HU₁₅₆ • 2013 PX₇₄ • 2014 DR₁₄₃ • 2014 JP₈₀ • 2014 JR₈₀ • 2014 MH₇₀ • 2014 WQ₅₀₉ • 2014 WQ₅₁₀ • 2017 OF₆₉
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Twotinos | 2000 QL₂₅₁ • 2001 KA₇₇ • 2001 UP₁₈ • 2002 WC₁₉ • 2003 UY₄₁₃ • 2005 CA₇₉ • 2005 RS₄₃ • 2007 JJ₄₃ • 2007 PS₄₅ • 2010 EP₆₅ • 2010 RO₆₄ • 2012 JH₆₇ • 2012 VB₁₁₆ • 2013 FZ₂₇ • 2013 HV₁₅₆ • 2013 UK₁₅ • 2014 AM₅₅ • 2014 DO₁₄₃ • 2014 JS₈₀ • 2014 QS₄₄₁ • 2014 RL₇₄ • 2014 WT₆₉ • 2014 XY₄₀ • 2015 BE₅₁₉ • 2021 LN₄₃
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Cubewanos | Altjira • Chaos • 420356 Praamzius • Salacia • Varda • Varuna • 1998 SN₁₆₅ • 1999 CL₁₁₉ • 2000 AF₂₅₅ • 2000 CO₁₀₅ • 2001 CZ₃₁ • 2001 QS₂₉₇ • 2001 QU₂₉₇ • 2001 QT₃₂₂ • 2002 AW₁₉₇ • 2002 CX₂₂₄ • 2002 CY₂₄₈ • 2002 KW₁₄ • 2002 KX₁₄ • 2002 MS₄ • 2002 PQ₁₄₅ • 2002 UX₂₅ • 2002 VT₁₃₀ • 2002 XE₉₁ • 2003 HC₅₇ • 2003 QW₉₀ • 2003 UB₂₉₂ • 2003 WQ₁₈₈ • 2004 DH₆₄ • 2004 GV₉ • 2004 NT₃₃ • 2004 PV₁₀₇ • 2004 PF₁₁₅ • 2004 TY₃₆₄ • 2004 UX₁₀ • 2005 LB₅₄ • 2005 RN₄₃ • 2005 UQ₅₁₃ • 2007 XV₅₀ • 2008 AP₁₂₉ • 2008 NW₄ • 2008 SP₂₆₆ • 2009 YR₂₆ • 2010 AH₂ • 2010 FX₈₆ • 2010 JK₁₂₄ • 2010 PK₆₆ • 2010 RN₆₄ • 2010 RD₁₈₈ • 2010 RF₁₈₈ • 2010 SS₄₃ • 2010 VQ₁₁ • 2010 VR₁₁ • 2010 WN₇₅ • 2011 JF₃₁ • 2011 LP₂₉ • 2011 OA₆₀ • 2012 BW₁₅₄ • 2012 VR₁₂₈ • 2013 FC₂₈ • 2013 JW₆₃ • 2013 MA₁₂ • 2013 RV₁₂₄ • 2013 XB₂₆ • 2014 BV₆₄ • 2014 BX₆₄ • 2014 CQ₂₃ • 2014 DE₁₄₃ • 2014 DF₁₄₃ • 2014 DM₁₄₃ • 2014 DN₁₄₃ • 2014 EA₅₂ • 2014 FU₇₁ • 2014 FW₇₁ • 2014 GT₅₃ • 2014 GW₅₃ • 2014 JC₉₂ • 2014 KW₁₀₁ • 2014 LR₂₈ • 2014 LT₂₈ • 2014 MY₆₉ • 2014 NB₆₆ • 2014 OD₃₉₄ • 2014 OE₃₉₄ • 2014 QX₄₄₁ • 2014 TC₈₆ • 2014 TD₈₆ • 2014 UP₂₂₄ • 2014 UQ₂₂₄ • 2014 US₂₂₄ • 2014 VU₃₇ • 2014 WH₅₀₉ • 2014 WJ₅₀₉ • 2014 WP₅₀₉ • 2014 WU₅₀₉ • 2014 WZ₅₀₉ • 2014 WA₅₁₀ • 2014 WL₆₁₆ • 2014 YZ₄₉ • 2014 YA₅₀ • 2014 YB₅₀ • 2015 AN₂₈₁ • 2015 BQ₅₁₈ • 2015 BT₅₁₈ • 2015 BV₅₁₈ •2015 BZ₅₁₈ • 2015 FL₃₄₅ • 2015 OV₇₉ • 2015 PY₃₃₀ • 2016 FP₅₉ • 2016 FK₁₆₄ • 2016 LX₈₉ • 2016 PO₂₉₆ • 2017 OG₆₉ 2021 CJ₄₆ • 2021 DS₁₅
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Other KBOs | 1999 CC₁₅₈ • 1999 CD₁₅₈ • 2001 YH₁₄₀ • 2002 GD₃₂ • 2002 GJ₃₂ • 2002 XW₉₃ • 2003 UX₂₉₂ • 2003 YO₁₇₉ • 2008 QB₄₃ • 2010 HE₇₉ • 2010 MQ₁₁₆ • 2010 OO₁₂₇ • 2010 TY₅₃ • 2010 VK₂₀₁ • 2010 VL₂₀₁ • 2010 VV₂₂₄ • 2010 VW₂₂₄ • 2011 FW₆₂ • 2011 GM₂₇ • 2011 GZ₆₁ • 2012 HG₈₄ • 2013 EJ₁₅₄ • 2013 RM₉₈ • 2013 XC₂₆ • 2014 BZ₅₇ • 2014 CO₂₃ • 2014 DK₁₄₃ • 2014 FT₇₁ • 2014 FY₇₁ • 2014 GU₅₃ • 2014 GX₅₃ • 2014 HZ₁₉₉ • 2014 LO₂₈ • 2014 JJ₈₀ • 2014 MA₇₀ • 2014 QW₄₄₁ • 2014 QY₄₄₁ • 2014 QA₄₄₂ • 2014 SH₃₄₉ • 2014 TZ₈₅ • 2014 UM₃₃ • 2014 UO₂₂₄ • 2014 WG₅₀₉ • 2014 WW₅₀₉ • 2014 WY₅₀₉ • 2014 XR₄₀ • 2014 XS₄₀ • 2015 AH₂₈₁ • 2015 AQ₂₉₃ • 2015 BX₅₁₈ • 2015 DZ₂₅₀ • 2015 FG₃₄₅
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Damocloids | 2003 HN₅₇ • 2003 UA₂₉₂
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SDOs | Gǃkúnǁ`hòmdímà • Dziewanna • 1996 GQ₂₁ • 1996 TL₆₆ • 1999 DE₉ • 1999 KR₁₆ • 2000 CQ₁₀₅ • 2000 OM₆₇ • 2000 PE₃₀ • 2000 YW₁₃₄ • 2001 FZ₁₇₃ • 2001 KC₇₇ • 2001 QX₃₂₂ • 2001 UR₁₆₃ • 2002 PJ₁₄₉ • 2002 TC₃₀₂ • 2003 UY₁₁₇ • 2003 UA₄₁₄ • 2004 OJ₁₄ •2004 PG₁₁₅ • 2004 XA₁₉₂ • 2005 QU₁₈₂ • 2005 RM₄₃ • 2005 SD₂₇₈ • 2006 QH₁₈₁ • 2007 OC₁₀ • 2007 TG₄₂₂ • 2008 OG₁₉ • 2008 QY₄₀ • 2010 ER₆₅ • 2010 ET₆₅ • 2010 JO₁₇₉ • 2010 KZ₃₉ • 2010 OE₁₅₃ • 2010 PT₆₆ • 2010 PU₇₅ • 2010 QQ₇ • 2010 RF₄₃ • 2010 RE₆₄ • 2010 TJ • 2010 VW₁₁ • 2010 VZ₉₈ • 2011 HP₈₃ • 2011 WJ₁₅₇ • 2012 AZ₂₅ • 2013 AP₁₈₃ • 2013 AT₁₈₃ • 2013 FY₂₇ • 2013 FS₂₈ • 2013 JH₆₄ • 2013 PV₇₄ • 2013 SR₁₀₂ • 2013 SF₁₀₆ • 2013 YJ₁₅₁ • 2014 AN₅₅ • 2014 EZ₅₁ • 2014 FC₆₉ • 2014 FJ₇₂ • 2014 HA₂₀₀ • 2014 HF₂₀₀ • 2014 JU₈₀ • 2014 JW₈₀ • 2014 LV₂₈ • 2014 OJ₃₉₄ • 2014 SV₃₄₉ • 2014 UR₂₂₄ • 2014 UZ₂₂₄ • 2014 UN₂₂₅ • 2014 WD₅₁₀ • 2014 WS₅₁₀ • 2014 XV₄₀ • 2014 YE₅₀ • 2014 YF₅₀ • 2014 YK₅₀ • 2014 YC₉₂ • 2015 AM₂₈₁ • 2015 BD₅₁₉ • 2015 BP₅₁₉ •2015 DU₂₄₉ • 2015 KH₁₆₂ • 2015 KF₁₇₂ • 2015 MQ₂₀₄ • 2015 RR₂₄₅ • 2015 VO₁₆₆ • 2015 VG₁₆₈ • 2015 VJ₁₆₈ • 2016 FX₅₈ • 2017 FO₁₆₁ • 2017 OK₆₉ • 2017 SN₁₃₂ • 2018 AG₃₇ • 2018 VG₁₈ • 2020 BE₁₀₂ • 2020 FY₃₀ • 2020 FA₃₁ • 2020 FB₃₁ • 2021 CK₄₆ • 2021 DP₁₅ • 2021 DR₁₅ • 2021 DG₁₇ • 2021 LL₃₇ • 2022 QF₂₆₁ • 2023 FS₅₄
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Detached | Alicanto 2000 CR₁₀₅ • 2003 FY₁₂₈ • 2003 HL₅₇ • 2003 QX₁₁₃ • 2004 XR₁₉₀ • 2005 TB₁₉₀ • 2008 ST₂₉₁ • 2010 DN₉₃ • 2014 FC₇₂ • 2014 JM₈₀ • 2014 ST₃₇₃ • 2014 US₂₇₇ • 2020 MK₅₃
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Sednoids | 2012 VP₁₁₃
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Navbox Note | This navbox contains all consensus dwarf planet candidates and also contains all objects with potential of candidacy, even if not all groups agree.
Bolded items are major, relatively well known objects or consensus dwarf planets. |