 Lightcurve-based 3D model of 86 Semele | |
| Discovery | |
|---|---|
| Discovered by | Friedrich Tietjen |
| Discovery date | 4 January 1866 |
| Designations | |
| Pronunciation | /ˈsɛmɪlə/ |
Named after | Semele |
| Main belt | |
| Adjectives | Semelean /sɛmɪˈleɪən/ |
| Orbital characteristics | |
| Epoch 9 June 2026 (JD 2461200.5) | |
| Uncertainty parameter 0 | |
| Aphelion | 3.7801 AU |
| Perihelion | 2.4269 AU |
| 3.1035 AU | |
| Eccentricity | 0.2180 |
| 1,996.99 d (5.47 a) | |
Average orbital speed | 16.69 km/s |
| 100.203° | |
| Inclination | 4.8200° |
| 86.042° | |
| 308.721° | |
| TJupiter | 3.179 |
| Physical characteristics | |
| Dimensions | 120.6 km |
| Mass | (1.11±0.21)×1018 kg |
Mean density | 1.59 g/cm3 |
Equatorial surface gravity | 0.0337 m/s² |
Equatorial escape velocity | 0.0638 km/s |
| 16.641±0.001 h | |
| 0.047 | |
| C | |
| 8.54 | |
86 Semele is a large and very dark main-belt asteroid with an orbital period of 5.5 years. It is rotating with a period of 16.6 hours, and varies in magnitude by 0.13 during each cycle. This object is classified as a C-type asteroid and is probably composed of carbonates.
Semele was discovered by German astronomer Friedrich Tietjen on 4 January 1866. It was his first and only asteroid discovery. It is named after Semele, the mother of Dionysus in Greek mythology.
The orbit of 86 Semele places it in a 13:6 mean motion resonance with the planet Jupiter. The computed Lyapunov time for this asteroid is only 6,000 years, indicating that it occupies a chaotic orbit that will change randomly over time because of gravitational perturbations of the planets. This Lyapunov time is the second lowest among the first 100 named minor planets.
