133 Cyrene
133 Cyrene is a fairly large and very bright main-belt asteroid that was discovered by J. C. Watson on 16 August 1873 in Ann Arbor, Michigan, and named after Cyrene, a nymph, daughter of king Hypseus and beloved of Apollo in Greek mythology. It is classified as an S-type asteroid based upon its spectrum. It is listed as a member of the Hecuba group of asteroids that orbit near the 2:1 mean-motion resonance with Jupiter.Discovery and naming
Cyrene was discovered on 16 August 1873 by astronomer James Craig Watson at Ann Arbor, Michigan, United States. Its discovery, alongside that of 132 Aethra, was announced in the journal Astronomische Nachrichten on 30 August. The asteroid was given the name Cyrene after the Greek mythological figure Cyrene, daughter of the Lapithian king Hypseus. With the god Apollo, she bore her two sons Aristaeus and Idmon.Orbit
Cyrene is a main belt asteroid, orbiting the Sun at an average distance—its semi-major axis—of 3.07 astronomical units. Along its 5.39 year long orbit, its distance from the Sun varies from 2.67 AU at perihelion to 3.47 AU at aphelion due to its orbital eccentricity of 0.13. It has an orbital inclination of 7.22° with respect to the ecliptic plane.Physical characteristics
In the Tholen classification system, it is categorized as a stony SR-type asteroid. Photometric observations of this asteroid at the Altimira Observatory in 1985 gave a light curve with a period of 12.707 ± 0.015 hours and a brightness variation of 0.22 in magnitude. This result matches previous measurements reported in 1984 and 2005.