Info

pluto

Pluto
Discovery
Discovered by Clyde W. Tombaugh
Discovery date February 18, 1930
Designations
MPC designation 134340 Pluto
Pronunciation /ˈplt/
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
  • 1,187±4 km[4]
  • 0.1863 Earths
Flattening <1%[4]
Surface area
  • 1.77×107 km2[c]
  • 0.035 Earths
Volume
  • (7.006±0.071)×109 km3[d]
  • 0.00647 Earths
Mass
  • (1.303±0.003)×1022 kg[4]
  • 0.00218 Earths
  • 0.177 Moons
Mean density
1.860±0.013 g/cm3[4]
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 orbit)[1]
North pole right ascension
132.993°[5]
North pole declination
−6.163°[5]
Albedo 0.49 to 0.66 (geometric, varies by 35%)[1][6]
Surface temp.minmeanmax
Kelvin 33 K 44 K (−229 °C) 55 K
Apparent magnitude
13.65[1] to 16.3[7]
(mean is 15.1)[1]
Absolute magnitude (H)
−0.7[8]
Angular diameter
0.06″ to 0.11″[1][g]
Atmosphere
Surface pressure
1.0 Pa (2015)[4][10]
Composition by volume Nitrogen, methane, carbon monoxide[9]