Prometheus (moon)
Prometheus image from Cassini (December 26, 2009) | |
| Discovery | |
|---|---|
| Discovered by | Stewart A. Collins D. Carlson Voyager 1 |
| Discovery date | 24 October 1980 |
| Designations | |
Designation | Saturn XVI |
| Pronunciation | /prəˈmiːθiːəs/ |
Named after | Προμηθεύς Promētheys |
| Adjectives | Promethean, -ian /prəˈmiːθiːən/ |
| Orbital characteristics | |
| 139378 km | |
| Eccentricity | 0.00223 |
| 0.612990 d | |
| Inclination | 0.008° |
| Satellite of | Saturn |
| Physical characteristics | |
| Dimensions | 137.0 × 81.0 × 56.2 km (± 1.0 × 2.8 × 0.8 km) |
| 85.6±1.4 km | |
| Volume | 327740±1710 km3 |
| Mass | (1.59720±0.00072)×1017 kg |
Mean density | 0.4873±0.0026 g/cm3 |
| 0.0007–0.0056 m/s2 | |
| 0.018 km/s at longest axis to 0.028 km/s at poles | |
| synchronous | |
| assumed zero | |
| Albedo | 0.67±0.07 |
| Temperature | ≈ 74 K |
Prometheus /prəˈmiːθiːəs/ is an inner satellite of Saturn. It was discovered on 24 October 1980 from images taken by the Voyager 1 probe, and was provisionally designated S/1980 S 27. In late 1985 it was officially named after Prometheus, a Titan in Greek mythology. It is also designated Saturn XVI.
Prometheus is extremely elongated, measuring approximately 137 km × 81 km × 56 km (85 mi × 50 mi × 35 mi). The surface is heavily cratered, giving it a similar appearance to nearby Epimetheus and Janus. It has several ridges and valleys and a number of impact craters of about 20 km (12 mi) diameter are visible. From its very low density and relatively high albedo, it is likely that Prometheus is a very porous icy body.