Info

uranus

Uranus
Discovery
Discovered by William Herschel
Discovery date March 13, 1781
Designations
Pronunciation /ˈjʊərənəs/ or/jʊˈrnəs/[1][2]
Adjectives Uranian
Orbital characteristics[7][a]
Epoch J2000
Aphelion 20.11 AU
(3,008 Gm)
Perihelion 18.33 AU
(2,742 Gm)
Semi-major axis
19.2184 AU
(2,875.04 Gm)
Eccentricity 0.046381
Orbital period
  • 84.0205 yr
  • 30,688.5 d[3]
  • 42,718 Uranian solar days[4]
Synodic period
369.66 days[5]
Average orbital speed
6.80 km/s[5]
Mean anomaly
142.238600°
Inclination 0.773° to ecliptic
6.48° to Sun's equator
1.02° to invariable plane[6]
Longitude of ascending node
74.006°
Argument of perihelion
96.998857°
Known satellites 27
Physical characteristics
Mean radius
25,362±7 km[8][b]
Equatorial radius
25,559±4 km
4.007 Earths[8][b]
Polar radius
24,973±20 km
3.929 Earths[8][b]
Flattening 0.0229±0.0008[c]
Circumference 159,354.1 km[3]
Surface area
8.1156×109 km2[3][b]
15.91 Earths
Volume 6.833×1013 km3[5][b]
63.086 Earths
Mass

(8.6810±0.0013)×1025 kg
14.536 Earths[9]

GM=5,793,939±13 km3/s2
Mean density
1.27 g/cm3[5][b]
Surface gravity

8.69 m/s2[5][b]
0.886 g

0.210
Moment of inertia factor
0.23[10]
Escape velocity
21.3 km/s[5][b]
Sidereal rotation period
0.71833 d
17 h 14 min 24 s[8]
Equatorial rotation velocity
2.59 km/s
9,320 km/h
Axial tilt
97.77° (to orbit)[5]
North pole right ascension
17h 9m 15s
257.311°[8]
North pole declination
−15.175°[8]
Albedo 0.300 (Bond)
0.51 (geom.)[5]
Surface temp.minmeanmax
1 bar level[11]   76 K (−197.2 °C)  
0.1 bar
(tropopause)[12]
47 K 53 K 57 K
Apparent magnitude
5.9[13] to 5.32[5]
Angular diameter
3.3″ to 4.1″[5]
Atmosphere[12][14][15][d]
Scale height
27.7 km[5]
Composition by volume

(Below 1.3 bar)
Gases:

  • 83 ± 3% hydrogen (H2)
  • 15 ± 3% helium (He)
  • 2.3% methane (CH4)
  • 0.009% (0.007–0.015%) hydrogen deuteride (HD)

Ices:

  • ammonia (NH3)
  • water (H2O)
  • ammonium hydrosulfide (NH4SH)
  • methane hydrate