78 Diana

78 Diana is a large and dark main-belt asteroid. It was discovered by German astronomer Robert Luther on March 15, 1863, and named after Diana, Roman goddess of the hunt. The asteroid is orbiting the Sun at a distance of with a period of 4.24 years and an eccentricity of 0.207. The orbital plane is tilted at an angle of 8.688° relative to the plane of the ecliptic. Its composition is carbonaceous and primitive.
Photometric observations of this asteroid during 1986 and 2006–08 gave a light curve with a rotation period of 7.2991 hours and a brightness variation in the range 0.02–0.104 magnitude. Based upon radar data, the near surface solid density of the asteroid is 2.7. 78 Diana occulted a star on September 4, 1980. A diameter of 116 km was measured, closely matching the value given by the IRAS satellite.
Diana is expected to pass about from (29075) 1950 DA on August 5, 2150. Main-belt asteroid 4217 Engelhardt will pass about from 1950 DA in 2736.