|Discovered by||Friedrich Tietjen|
|Discovery date||January 4, 1866|
|Epoch December 31, 2006 (JD 2454100.5)|
|Aphelion||562.652 Gm (3.761 AU)|
|Perihelion||369.116 Gm (2.467 AU)|
|465.884 Gm (3.114 AU)|
|2,007.366 d (5.50 a)|
Average orbital speed
Equatorial surface gravity
Equatorial escape velocity
Semele (minor planet designation: 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.
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.