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Encyclopedia > Saturn > Inner satellites IV
PROMETHEUS ET PANDORA :
SATELLITES XVI AND XVII OF SATURN,
"SHEPHERDS" OF THE RINGS
Prometheus (Saturn XVI) was discovered by S.Collins in 1980 from Voyager photos. Its revolution period is 14 hours and 43 minutes.
Pandora (Saturn XVII) was discovered by Collins in 1980 from Voyager photos. Its revolution period is 15 hours.
| Characteristics | Values for Prometheus: | Values for Pandora: |
|---|---|---|
| distance to Saturn in km | 139 350 | 141 700 |
| revolution period | 0.613 day | 0.628 day |
| orbital velocity | 17 km/s | 16,4 km/s |
| average size | 100x149x68 km | 82x110x62 km |
| visual magnitude | 15.8 | 15.5 |
| reflectivity (geometric albedo) | 0.6 | ? |
| inclination of the orbit on the equator of Saturn | 0 | 0 |
| eccentricity of the orbit | 0.002 | 0.004 |
| escape velocity | 22 m/s | 20 m/s |
Opposite: the Voyager images. Prometheus and Pandora rotate each on a different side of the ring they "shepherd". Their gravitational influence maintains the shape of the ring.
Origin of the name : click here.