| Minorplanet: | yes |
| Background: |
|
| 133 Cyrene | |
| Discovered: | 16 August 1873 |
| Mpc Name: | (133) Cyrene |
| Alt Names: | A873 QA; 1910 NB; 1936 HO; 1948 QC; 1959 UR |
| Pronounced: | [1] |
| Adjective: | Cyrenean, Cyrenian |
| Epoch: | 31 July 2016 (JD 2457600.5) |
| Semimajor: | 3.0649AU |
| Perihelion: | 2.64706AU |
| Aphelion: | 3.48274abbr=onNaNabbr=on |
| Eccentricity: | 0.13633 |
| Period: | 5.37 yr (1959.9 d) |
| Inclination: | 7.21561° |
| Asc Node: | 319.066° |
| Arg Peri: | 289.646° |
| Avg Speed: | 17.03 km/s |
| Mass: | 3.1 × 1017 kg |
| Density: | 2.0? g/cm3 |
| Surface Grav: | 0.0186 m/s² |
| Escape Velocity: | 0.0352 km/s |
| Rotation: | 12.708abbr=onNaNabbr=on 12.707 h (0.5295 d) |
| Abs Magnitude: | 7.98, 7.990 |
| Albedo: | 0.2563 |
| Mean Motion: | / day |
| Observation Arc: | 142.65 yr (52104 d) |
| Uncertainty: | 0 |
| Moid: | 1.64415AU |
| Jupiter Moid: | 1.65199AU |
| Tisserand: | 3.206 |
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.
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.