Pluto (minor-planet designation: 134340 Pluto) is a dwarf planet in the Kuiper belt, a ring of bodies beyond Neptune. It was the first Kuiper belt object to be discovered.
Pluto 2nd Astronomical symbol for Pluto
Nh-pluto-in-true-color 2x JPEG-edit-frame.jpg
Full-disc view of Pluto in near-true color, imaged by New Horizons[a]
Discovery
Discovered by Clyde W. Tombaugh
Discovery date February 18, 1930
Designations
MPC designation 134340 Pluto
Pronunciation /ˈpluːtoʊ/
Named after
Pluto
Minor planet category
Dwarf planet
Trans-Neptunian object
Plutoid
Kuiper belt object
Plutino
Adjectives Plutonian
Orbital characteristics[3][b]
Epoch J2000
Aphelion
49.305 AU
(7,375.93 Gm)
February, 2114
Perihelion
29.658 AU
(4,436.82 Gm)[1]
(September 5, 1989)[2]
Semi-major axis
39.48 AU
(5,906.38 Gm)
Eccentricity 0.2488
Orbital period
248.00 years[1]
90,560 d[1]
Synodic period
366.73 days[1]
Average orbital speed
4.67 km/s[1]
Mean anomaly
14.53 deg
Inclination
17.16°
(11.88° to Sun's equator)
Longitude of ascending node
110.299°
Argument of perihelion
113.834°
Known satellites 5
Physical characteristics
Mean radius
1,189.9±0.2 km[4]
0.1868 Earths
Flattening <1%[5]
Surface area
1.779×107 km2[c]
0.035 Earths
Volume
(7.057±0.004)×109 km3[d]
0.00651 Earths
Mass
(1.303±0.003)×1022 kg[5]
0.00218 Earths
0.177 Moons
Mean density
1.860±0.013 g/cm3[5]
Surface gravity
0.620 m/s2[e]
0.063 g
Escape velocity
1.212 km/s[f]
Sidereal rotation period
6.387230 d
6 d, 9 h, 17 m, 36 s
Equatorial rotation velocity
47.18 km/h
Axial tilt
122.53° (to #########
###### pole right ascension
132.993°[6]
North pole declination
−6.163°[6] |