Basic data for Pluto

mean distance from Sun 5,910,000,000 km (39.5 AU)

eccentricity of orbit 0.251

inclination of orbit to ecliptic 17.1°

Plutonian year (sidereal period of revolution) 247.69 Earth years

visual magnitude at mean opposition 15.1

mean synodic period* 366.74 Earth days

mean orbital velocity 4.72 km/s

radius 1,172 km

mass 1.2 x 10²² kg

mean density about 2 g/cm³

mean surface gravity 58 cm/s

escape velocity 1.1 km/s

rotation period (Plutonian sidereal day) 6.3873 Earth days (retrograde)

Plutonian mean solar day** 6.3874 Earth days

inclination of equator to orbit (obliquity) 120°

mean surface temperature about 40 K (-387 °F, -233 °C)

surface pressure (near perihelion) about 10^-5 bar

number of known moons 3

*Time required for Pluto to return to the same position in the sky relative to the Sun as seen from Earth.

**Smallness of deviation from sidereal day is due to Pluto's huge orbit.