Uranus  
Uranus in 1986 by Voyager 2
Discovery
Discovered by William Herschel
Discovery date March 13, 1781
Designations
Pronunciation
Adjective Uranian
Orbital characteristics
Epoch J2000
Aphelion
  • 3,004,419,704 km
  • 20.083 305 26 AU
Perihelion
  • 2,748,938,461 km
  • 18.375 518 63 AU
Semi-major axis
  • 2,876,679,082 km
  • 19.229 411 95 AU
Eccentricity 0.044 405 586
Orbital period
  • 30,799.095 days
  • 84.323 326 yr
  • 42,718 Uranus solar days
Synodic period 369.66 days
Average orbital speed 6.81 km/s
Mean anomaly 142.955 717°
Inclination 0.772 556° to Ecliptic
6.48° to Sun's equator
1.02° to Invariable plane
Longitude of ascending node 73.989 821°
Argument of perihelion 96.541 318°
Satellites 27
Physical characteristics
Equatorial radius 25,559 ± 4 km
4.007 Earths
Polar radius 24,973 ± 20 km
3.929 Earths
Flattening 0.022 9 ± 0.000 8
Circumference 159,354.1 km
Surface area 8.115 6×10
15.91 Earths
Volume 6.833×10
63.086 Earths
Mass (8.6810 ± 0.0013)×1025kg
14.536 Earths
GM=5 793 939 ± 13 km3/s2
Mean density 1.27 g/cm
Equatorial surface gravity 8.69 m/s
0.886 g
Escape velocity 21.3 km/s
Sidereal rotation
period
−0.718 33 day
17 h 14 min 24 s
Equatorial rotation velocity 2.59 km/s
9,320 km/h
Axial tilt 97.77°
North pole right ascension 17 h 9 min 15 s
257.311°
North pole declination −15.175°
Albedo 0.300 (Bond)
0.51 (geom.)
Surface temp.
   1 bar level
   0.1 bar
(tropopause)
min mean max
76 K
49 K 53 K 57 K
Apparent magnitude 5.9
Angular diameter 3.3"–4.1"
Atmosphere
Scale height 27.7 km
Composition (Below 1.3 bar)
83 ± 3% hydrogen (H2)
15 ± 3% helium
2.3% methane
0.009%
(0.007–0.015%)
hydrogen deuteride (HD)
Ices:
ammonia
water
ammonium hydrosulfide (NH4SH)
methane (CH4)

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Uranus, which is released under the Creative Commons Attribution-Share-Alike License 3.0