Sponsored by the Institute of Physics   Planets   Mercury   Venus   Earth   Mars   Jupiter   Saturn   Uranus   Neptune   Pluto Asteroids Comets Constellations Sunrise and Sunset Times Moon Phases SI Units Symbols   Printer Version Astronomy Planets - Mercury Bulk Parameters |  Orbital Parameters Mean Orbital Elements (J2000) | Magnetospheric Parameters Observational Parameters | Atmospheric Parameters Satellites   Bulk Parameters Mass 0.3302 × 1024 kg Volume 6.083 × 1010 km3 Equatorial Radius 2439.7 km Polar Radius 2439.7 km Volumetric Mean Radius 2439.7 km Ellipticity 0.0000 Mean Density 5427 kg m-3 Surface Gravity 3.70 m s-2 Escape Velocity 4.3 km s-1 GM 0.02203 × 106 km3 s-2 Bond Albedo 0.119 Visual Geometric Albedo 0.106 Visual Magnitude -0.42 Solar Irradiance 9126.6 W m-2 Black-Body Temperature 442.5 K Moment of Inertia 0.33 I MR-2 Orbital Parameters Semimajor Axis 57.91 × 106 km Sidereal Orbit Period 87.969 days Tropical Orbit Period 87.968 days Perihelion 46.00 × 106 km Aphelion 69.82 × 106 km Synodic Period 115.88 days Mean Orbital Velocity 47.87 km s-1 Maximum Orbital Velocity 58.98 km s-1 Minimum Orbital Velocity 38.86 km s-1 Orbital Inclination 7.00 ° Orbital Eccentricity 0.2056 Sidereal Rotation Period 1407.6 hours Length of Day 4222.6 hours Obliquity to Orbit 0.01 Mean Orbital Elements (J2000) Semimajor Axis 0.38709893 AU Orbital Eccentricity 0.20563069 Orbital Inclination 7.00487° Longitude of Ascending Node 48.33167° Longitude of Perihelion 77.45645° Mean Longitude 252.25084° Magnetospheric Parameters Dipole Field Strength 0.0033 gauss-Rh3 [*] Dipole Tilt to Rotational Axis 169° Longitude of Tilt 285° (from Mercury I flyby) 115° (from Mercury III flyby) Rh = Mercurian Radii (2439.7 km) Observational Parameters Maximum Apparent Diameter from Earth 13 arc seconds Minimum Apparent Diameter from Earth 4.5 arc seconds Maximum Distance from Earth 221.9 × 106 km Minimum Distance from Earth 77.3 × 106 km Apparent Magnitude from Opposition -1.9 Atmospheric Parameters Surface Pressure 10-15 bar Average Temperature 440 K (590K to 725K on sunward side) Oxygen O2 42% Sodium Na 29% Hydrogen H2 22% Helium He 6% Potassium K 0.5% Argon Ar Trace Carbon Dioxide CO2 Trace Water H2O Trace Nitrogen N2 Trace Xenon Xe Trace Krypton Kr Trace Neon Ne Trace Satellites Mercury has no known satellites   [ H O M E ] [ S C I E N C E ] [ M A T H S ] [ A S T R O N O M Y ] Download | Shop | Contact | About   Page compiled: Wed Sep 05 18:37:57 GMT+01:00 2001