216 Kleopatra
216 Kleopatra is a large M-type asteroid with a mean diameter of 120 kilometers (75 miles) and is noted for its elongate bone or dumbbell shape. It was discovered on 10 April 1880 by Austrian astronomer Johann Palisa at the Austrian Naval Pola Observatory, in what is now Pula, Croatia, and was named after Cleopatra, the famous Egyptian queen. It has two small minor-planet moons which were discovered in 2008 and later named Alexhelios and Cleoselene.
| Discovery | |
|---|---|
| Discovered by | J. Palisa |
| Discovery site | Pola Obs. |
| Discovery date | 10 April 1880 |
| Designations | |
MPC designation | (216) Kleopatra |
| Pronunciation | /ˌkliəˈpætrə/ |
Named after | Cleopatra (Egyptian queen) |
Alternative designations | A880 GB · 1905 OA 1910 RA |
Minor planet category | main-belt · (central) background |
| Adjectives | Kleopatrian, Kleopatrean |
| Orbital characteristics | |
| Epoch 23 March 2018 (JD 2458200.5) | |
| Uncertainty parameter 0 | |
| Observation arc | 137.60 yr (50,259 d) |
| Aphelion | 3.4951 AU |
| Perihelion | 2.0931 AU |
Semi-major axis | 2.7941 AU |
| Eccentricity | 0.2509 |
Orbital period (sidereal) | 4.67 yr (1,706 d) |
Mean anomaly | 346.24° |
Mean motion | 0° 12m 39.6s / day |
| Inclination | 13.113° |
Longitude of ascending node | 215.36° |
| 180.11° | |
| Known satellites | 2 (Alexhelios · Cleoselene) |
| Physical characteristics | |
| Dimensions | c/a = 0.18±0.02 (276 × 94 × 78) ± 15% km |
Mean diameter | 118±2 km 122±30 km 103±4 km 121.6±1.6 km 135±2 km |
| Mass | (3.0±0.3)×1018 kg (2.97±0.02)×1018 kg |
Mean density | 3.45±0.41 g/cm3 ca. 4.5 g/cm3 (most likely between 3.6±0.4 g/cm3 for D = 135 km and 5.4±0.4 g/cm3 for D = 109 km) |
Synodic rotation period | 5.385280±0.000001 h |
| 0.152 (calculated) 0.1164±0.004 0.170 0.149±0.005 0.1111±0.0336 0.1068 0.200±0.028 | |
| M (Tholen) · Xe (SMASS) M B–V = 0.713 U–B = 0.238 | |
| 7.30 7.35±0.02 · 7.45 | |
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