Pluto in true color as imaged by the
New Horizons spacecraft in July 2015.
[a]
|
|||||||||
| Discovery | |||||||||
|---|---|---|---|---|---|---|---|---|---|
| Discovered by | Clyde W. Tombaugh | ||||||||
| Discovery site | Lowell Observatory | ||||||||
| Discovery date | February 18, 1930 | ||||||||
| Designations | |||||||||
| (134340) Pluto | |||||||||
| Pronunciation | /ˈpluːtoʊ/ ⓘ | ||||||||
|
Named after
|
Pluto | ||||||||
| Adjectives | Plutonian /pluːˈtoʊniən/[1] | ||||||||
| Symbol | .svg){kind=small} or .svg){kind=small} |
||||||||
| Orbital characteristics[2][b] | |||||||||
| Epoch J2000 | |||||||||
| Earliest precovery date | August 20, 1909 | ||||||||
| Aphelion |
|
||||||||
| Perihelion | |||||||||
|
|||||||||
| Eccentricity | 0.2488 | ||||||||
| 366.73 days[3] | |||||||||
|
Average
orbital speed
|
4.743 km/s[3] | ||||||||
| 14.53 deg | |||||||||
| Inclination |
|
||||||||
| 110.299° | |||||||||
| 113.834° | |||||||||
| Known satellites | 5 | ||||||||
| Physical characteristics | |||||||||
| Dimensions | 2,376.6±1.6 km (observations consistent with a sphere, predicted deviations too small to be observed)[5] | ||||||||
| Flattening | <1%[7] | ||||||||
|
|||||||||
| Volume |
|
||||||||
| Mass | |||||||||
|
Mean
density
|
1.853±0.004 g/cm3[8] | ||||||||
|
Equatorial
surface gravity
|
0.620 m/s2 (0.0632 g0)[e] | ||||||||
|
Equatorial
escape velocity
|
1.212 km/s[f] | ||||||||
|
|||||||||
|
|||||||||
|
Equatorial rotation velocity
|
13.11 m/s[citation needed] | ||||||||
| 119.51° (to orbit)[3] | |||||||||
|
North pole
right ascension
|
132.993°[10] | ||||||||
|
North pole
declination
|
−6.163°[10] | ||||||||
| 0.52 geometric (locally 0.08–1.0)[3] 0.72 ± 0.07 Bond[3] |
|||||||||
|
|||||||||
| 13.65[3] to 16.3[11] (mean is 15.1)[3] |
|||||||||
| −0.44[12] | |||||||||
| 0.06″ to 0.11″[3][g] | |||||||||
| Atmosphere | |||||||||
|
Surface
pressure
|
1.0 Pa (2015)[7][13] (9.9×10−6 atm) | ||||||||
| Composition by volume | Nitrogen, methane, carbon monoxide[14] | ||||||||
|
Pluto in true color as imaged by the
New Horizons spacecraft in July 2015.
[a]
|
|||||||||
| Discovery | |||||||||
|---|---|---|---|---|---|---|---|---|---|
| Discovered by | Clyde W. Tombaugh | ||||||||
| Discovery site | Lowell Observatory | ||||||||
| Discovery date | February 18, 1930 | ||||||||
| Designations | |||||||||
| (134340) Pluto | |||||||||
| Pronunciation | /ˈpluːtoʊ/ ⓘ | ||||||||
|
Named after
|
Pluto | ||||||||
| Adjectives | Plutonian /pluːˈtoʊniən/[1] | ||||||||
| Symbol | or |
||||||||
| Orbital characteristics[2][b] | |||||||||
| Epoch J2000 | |||||||||
| Earliest precovery date | August 20, 1909 | ||||||||
| Aphelion |
|
||||||||
| Perihelion | |||||||||
|
|||||||||
| Eccentricity | 0.2488 | ||||||||
| 366.73 days[3] | |||||||||
|
Average
orbital speed
|
4.743 km/s[3] | ||||||||
| 14.53 deg | |||||||||
| Inclination |
|
||||||||
| 110.299° | |||||||||
| 113.834° | |||||||||
| Known satellites | 5 | ||||||||
| Physical characteristics | |||||||||
| Dimensions | 2,376.6±1.6 km (observations consistent with a sphere, predicted deviations too small to be observed)[5] | ||||||||
| Flattening | <1%[7] | ||||||||
|
|||||||||
| Volume |
|
||||||||
| Mass | |||||||||
|
Mean
density
|
1.853±0.004 g/cm3[8] | ||||||||
|
Equatorial
surface gravity
|
0.620 m/s2 (0.0632 g0)[e] | ||||||||
|
Equatorial
escape velocity
|
1.212 km/s[f] | ||||||||
|
|||||||||
|
|||||||||
|
Equatorial rotation velocity
|
13.11 m/s[citation needed] | ||||||||
| 119.51° (to orbit)[3] | |||||||||
|
North pole
right ascension
|
132.993°[10] | ||||||||
|
North pole
declination
|
−6.163°[10] | ||||||||
| 0.52 geometric (locally 0.08–1.0)[3] 0.72 ± 0.07 Bond[3] |
|||||||||
|
|||||||||
| 13.65[3] to 16.3[11] (mean is 15.1)[3] |
|||||||||
| −0.44[12] | |||||||||
| 0.06″ to 0.11″[3][g] | |||||||||
| Atmosphere | |||||||||
|
Surface
pressure
|
1.0 Pa (2015)[7][13] (9.9×10−6 atm) | ||||||||
| Composition by volume | Nitrogen, methane, carbon monoxide[14] | ||||||||
