Closest approach to earth: 34,600,000 miles. Mean distance from the sun: 141,600,000 miles. Period of rotation around the sun: 1.88089 years. Sideral rotation period: 24 hours, 37 minutes, 22.66 seconds. Mean surface atmospheric temperature: -23 degrees. Visual albedo: 0.159. Pole Star: BD 52, Degrees 2880. Visual magnitude at mean opposition: -2.01. Mass: 0.10174. Density: 3.93. Diameter: 0.532.