(The second value represents the quantity as a fraction of the terrestrial value.)
Mass 86.83e24 kg 14.536 GM 5.794e6 km3/s2 14.536 Equatorial radius 25,559 km 4.007 Polar radius 24,973 km 3.929 Flattening 22.927e-3 6.76 Mean density 1,318 kg/m3 0.239 Moment of inertia coefficient 0.225 0.680 J2 12e-3 11.1 Surface gravity 8.69 m/s2 0.889 Escape velocity 21.3 km/s 1.903
Semimajor axis 2.8696e9 km 19.182 Sidereal period 30,685.4 d 84.011 Tropical period 30,588.740 d 83.749 Eccentricity 0.04724 2.829 Inclination 0.773 deg Synodic period 369.66 d Mean orbital velocity 5.48 km/s 0.184
Bond albedo 0.90 2.338 Visual geometric albedo 0.51 1.390 Visual magnitude V(1,0) -7.19 Solar irradiance 3.71 W/m2 0.0027 Black-body temperature 35.9 K 0.145
Epoch 1994.0 North pole (RA and Dec) 257.34 deg / -15.09 deg Obliquity 97.86 deg Argument of prime meridian 277.31 deg at epoch Sidereal rotation rate -501.1600928 deg/d Sidereal rotation period 17.240 h* Magnetic coordinates (as determined by the Voyager 2 Radio Science experiment)
Dipole strength 0.228 gauss-Ru3 Dipole tilt to spin axis 58.6 deg Dipole offset 0.3 Ru, along the rotation axisNote: Ru denotes Uranian radii, here defined to be 25,600 km
Surface pressure >>100 bars Average temperature ~58 K Temperature at 1 bar ~76 K Density at 1 bar ~0.42 kg/m3 Wind speeds 0 to 200 m/s Scale height 27.7 km Mean molecular weight 2.64 g/mole Composition: Hydrogen (H2) 89% Helium (He) 11% Methane (CH4) ? ppm Aerosols: Ammonia ice; water ice; ammonia hydrosulfide; methane ice (?)
Epoch JD 2449360.5 Mean distance 19.249 AU Eccentricity 0.0469 Inclination 0.77 deg Longitude of ascending node 74.05 deg Longitude of perihelion 174.63 deg Mean longitude at epoch 287.46 deg