closest approach to Earth, 34,600,000 miles, mean distance from the sun, 141,600,000 miles, period of rotation about sun, 1.88089 years, sidereal rotation period, 24 hours, 37 minutes, 22.66 seconds, mean surface atmospheric temperature, minus 23 degrees, visual albedo, 0.159, pole star BD52, degrees 2,880, visual magnitude and mean opposition, minus 2.01, mass 0.107, density 3.31, diameter 0.532,
