106 Dione
Dione (minor planet designation: 106 Dione) is a large main-belt asteroid. It probably has a composition similar to 1 Ceres. It was discovered by J. C. Watson on October 10, 1868, and named after Dione, a Titaness in Greek mythology who was sometimes said to have been the mother of Aphrodite, the Greek goddess of love and beauty. It is listed as a member of the Hecuba group of asteroids that orbit near the 2:1 mean-motion resonance with Jupiter. The orbital period for this object is 5.66 years and it has an eccentricity of 0.17.
| Discovery | |
|---|---|
| Discovered by | James Craig Watson |
| Discovery date | 10 October 1868 |
| Designations | |
MPC designation | (106) Dione |
| Pronunciation | /daɪˈoʊniː/ |
Named after | Dione |
Alternative designations | A868 TA, 1902 TA |
Minor planet category | Main belt |
| Orbital characteristics | |
| Epoch 31 July 2016 (JD 2457600.5) | |
| Uncertainty parameter 0 | |
| Observation arc | 145.03 yr (52972 d) |
| Aphelion | 3.7032 AU (553.99 Gm) |
| Perihelion | 2.64584 AU (395.812 Gm) |
Semi-major axis | 3.17451 AU (474.900 Gm) |
| Eccentricity | 0.16653 |
Orbital period (sidereal) | 5.66 yr (2065.9 d) |
Average orbital speed | 16.61 km/s |
Mean anomaly | 51.5257° |
Mean motion | 0° 10m 27.336s / day |
| Inclination | 4.5972° |
Longitude of ascending node | 62.163° |
| 329.725° | |
| Earth MOID | 1.65175 AU (247.098 Gm) |
| Jupiter MOID | 1.73379 AU (259.371 Gm) |
| TJupiter | 3.175 |
| Physical characteristics | |
| Dimensions | 146.59±2.8 km 147.17 ± 3.34 km |
| Mass | (3.06 ± 1.54) × 1018 kg |
Mean density | 1.83 ± 0.92 g/cm3 |
Equatorial surface gravity | 0.0410 m/s² |
Equatorial escape velocity | 0.0775 km/s |
Synodic rotation period | 16.26 h (0.678 d) 16.26 ± 0.02 h |
| 0.0893±0.003 | |
| Temperature | ~156 K |
| G (Tholen) Cgh (Bus) | |
| 7.41 | |
Measurements made with the IRAS observatory give a diameter of 169.92±7.86 km and a geometric albedo of 0.07±0.01. By comparison, the MIPS photometer on the Spitzer Space Telescope gives a diameter of 168.72±8.89 km and a geometric albedo of 0.07±0.01. Dione was observed to occult a dim star on January 19, 1983, by observers in Denmark, Germany and the Netherlands. A diameter of 147±3 km was deduced, closely matching the value acquired by the IRAS satellite. As of 2012, the mean diameter derived through occultation measurements is 176.7±0.4 km.
Photometric observations of this asteroid collected during 2004–2005 show a rotation period of 16.26±0.02 hours with a brightness variation of 0.08±0.02 magnitude. It is classified as a rare G-type asteroid, suggesting it has a carbonaceous composition with phyllosilicate minerals also being detected.
One of Saturn's satellites is also named Dione.