Discovery | |
---|---|
Discovered by | James Craig Watson |
Discovery date | 16 August 1873 |
Designations | |
(133) Cyrene | |
Pronunciation | /saɪˈriËniË/[1] |
Named after | Cyrene (mythology) |
A910 NB; 1936 HO; 1948 QC; 1959 UR | |
Main belt | |
Adjectives | Cyrenean /saɪrɪˈniËÉ™n/, Cyrenian /saɪˈriËniÉ™n/[2] |
Orbital characteristics[3] | |
Epoch 31 July 2016 (JD 2457600.5) | |
Uncertainty parameter 0 | |
Observation arc | 142.65 yr (52104 d) |
Aphelion | 3.48274 AU (521.010 Gm) |
Perihelion | 2.64706 AU (395.995 Gm) |
3.06490 AU (458.503 Gm) | |
Eccentricity | 0.13633 |
5.37 yr (1959.9 d) | |
Average orbital speed | 17.03 km/s |
316.166° | |
0° 11m 1.273s / day | |
Inclination | 7.21561° |
319.066° | |
289.646° | |
Earth MOID | 1.64415 AU (245.961 Gm) |
Jupiter MOID | 1.65199 AU (247.134 Gm) |
TJupiter | 3.206 |
Physical characteristics | |
Dimensions | 66.57±6.0 km |
Mass | 3.1 × 1017 kg |
Mean density | 2.0? g/cm³ |
Equatorial surface gravity | 0.0186 m/s² |
Equatorial escape velocity | 0.0352 km/s |
12.708 h (0.5295 d)[3] 12.707 h (0.5295 d)[4] | |
0.2563±0.053[3] 0.2563[5] | |
Temperature | ~133 K |
S[5] | |
7.98,[3] 7.990[6] | |
Cyrene, minor planet designation 133 Cyrene, is a fairly large and very bright main-belt asteroid that was discovered by J. C. Watson on 16 August 1873, and named after Cyrene, a nymph, daughter of king Hypseus and beloved of Apollo in Greek mythology.[7] 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.[8]
In the Tholen classification system, it is categorized as a stony SR-type asteroid.[9] 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.[4]