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| Discovery | |||||||||
|---|---|---|---|---|---|---|---|---|---|
| Discovered by | Clyde W. Tombaugh | ||||||||
| Discovery date | February 18, 1930 | ||||||||
| Designations | |||||||||
| MPC designation | 134340 Pluto | ||||||||
| Pronunciation | how to say: /ˈpluːtoʊ/, | ||||||||
| dwarf planet, TNO, plutoid, KBO, plutino | |||||||||
| Adjectives | Plutonian | ||||||||
| Orbital characteristics | |||||||||
| Epoch J2000 | |||||||||
| Aphelion | 7,375,927,931 km 49.305 032 87 AU | ||||||||
| Perihelion | 4,436,824,613 km 29.658 340 67 AU | ||||||||
| 5,906,376,272 km 39.481 686 77 AU | |||||||||
| Eccentricity | 0.248 807 66 | ||||||||
| 90,613.305 days 248.09 years 14,164.4 Pluto solar days | |||||||||
| 366.73 days | |||||||||
Average orbital speed | 4.666 km/s | ||||||||
| Inclination | 17.141 75° 11.88° to Sun's equator | ||||||||
| 110.303 47° | |||||||||
| 113.763 29° | |||||||||
| Known satellites | 5 | ||||||||
| Physical characteristics | |||||||||
Mean radius | 1,187 ± 4 km 0.18 Earths | ||||||||
| 1.665×107 km² 0.033 Earths | |||||||||
| Volume | 6,39×109 km³ 0.0059 Earths | ||||||||
| Mass | (1.305 ± 0.007)×1022 kg 0.002 1 Earths 0.178 moon | ||||||||
Mean density | 2.03 ± 0.06 g/cm³ | ||||||||
| 0.658 m/s² 0.067 g | |||||||||
| 1.229 km/s | |||||||||
Sidereal rotation period | −6.387 230 day 6 d 9 h 17 m 36 s | ||||||||
Equatorial rotation velocity | 47.18 km/h | ||||||||
| 119.591 ± 0.014° (to orbit) | |||||||||
North pole right ascension | 133.046 ± 0.014° | ||||||||
North pole declination | −6.145 ± 0.014° | ||||||||
| Albedo | 0.49–0.66 (varies by 35%) | ||||||||
| |||||||||
| up to 13.65 (mean is 15.1) | |||||||||
| −0.7 | |||||||||
| Atmosphere | |||||||||
Surface pressure | 0.30 Pa (summer maximum) | ||||||||
| Composition by volume | nitrogen, methane, carbon monoxide | ||||||||
Pluto is a dwarf planet in the Solar System. Its formal name is 134340 Pluto, and its planetary symbol 
or 
. Pluto is the ninth largest body that moves around the Sun. Upon first being discovered, Pluto was considered a planet but was reclassified to a dwarf planet in 2006. It is the largest body in the Kuiper belt.
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