Pluto, imaged by the
New Horizons spacecraft, July 2015.
[a] The most prominent feature in the image, the bright, youthful plains of
Tombaugh Regio and
Sputnik Planitia, can be seen at right. It contrasts the darker, cratered terrain of
Belton Regio at lower left
|
|||||||||
| 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} (historically astronomical, now mostly astrological) or .svg){kind=small} (mostly astrological) |
||||||||
| 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] | ||||||||
| 122.53° (to orbit)[3] | |||||||||
|
North pole
right ascension
|
132.993°[10] | ||||||||
|
North pole
declination
|
−6.163°[10] | ||||||||
| 0.52 geometric[3] 0.72 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] | ||||||||
| Composition by volume | Nitrogen, methane, carbon monoxide[14] | ||||||||
|
Pluto, imaged by the
New Horizons spacecraft, July 2015.
[a] The most prominent feature in the image, the bright, youthful plains of
Tombaugh Regio and
Sputnik Planitia, can be seen at right. It contrasts the darker, cratered terrain of
Belton Regio at lower left
|
|||||||||
| 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 | (historically astronomical, now mostly astrological) or (mostly astrological) |
||||||||
| 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] | ||||||||
| 122.53° (to orbit)[3] | |||||||||
|
North pole
right ascension
|
132.993°[10] | ||||||||
|
North pole
declination
|
−6.163°[10] | ||||||||
| 0.52 geometric[3] 0.72 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] | ||||||||
| Composition by volume | Nitrogen, methane, carbon monoxide[14] | ||||||||
