Pandora (moon)

This article is about a moon of Saturn. For a fictional moon in Avatar film, see Fictional universe of Avatar.

For the asteroid, see 55 Pandora.

Pandora

Pandora, as imaged by Cassini
Discovery
Discovered by	Collins, Voyager 1
Discovery date	October, 1980
Orbital characteristics
Epoch December 31, 2003 (JD 2453005.5)
Semi-major axis	141720±10 km
Eccentricity	0.0042
Orbital period	0.628504213 d
Inclination	0.050°±0.004° to Saturn's equator
Satellite of	Saturn
Physical characteristics
Dimensions	104 × 81 × 64 km
Mean radius	40.7±1.5 km
Volume	≈ 280000 km3
Mass	(1.371±0.019)×1017 kg
Mean density	0.49±0.06 g/cm3
Surface gravity	0.0026–0.0060 m/s2
Escape velocity	≈ 0.019 km/s
Rotation period	synchronous
Axial tilt	zero
Albedo	0.6
Temperature	≈ 78 K

Pandora (/pænˈdɔərə/ pan-DOHR-ə; Greek: Πανδώρα) is an inner satellite of Saturn. It was discovered in 1980 from photos taken by the Voyager 1 probe, and was provisionally designated S/1980 S 26. In late 1985 it was officially named after Pandora from Greek mythology. It is also designated as Saturn XVII.

Pandora was thought to be an outer shepherd satellite of the F Ring. However, recent studies indicate that it does not play such a role, and that only Prometheus, the inner shepherd, contributes to the confinement of the narrow ring. It is more heavily cratered than nearby Prometheus, and has at least two large craters 30 kilometres (19 mi) in diameter. The majority of craters on Pandora are shallow as a result of being filled with debris. Ridges and grooves are also present on moon's surface.

The orbit of Pandora appears to be chaotic, as a consequence of a series of four 118:121 mean-motion resonances with Prometheus. The most appreciable changes in their orbits occur approximately every 6.2 years, when the periapsis of Pandora lines up with the apoapsis of Prometheus and the moons approach to within about 1,400 kilometres (870 mi). Pandora also has a 3:2 mean-motion resonance with Mimas.

From its very low density and relatively high albedo, it seems likely that Pandora is a very porous icy body. There is a lot of uncertainty in these values, however, so this remains to be confirmed.

Gallery

• 

  Voyager 2 image of Pandora (August 1981).

• 

  Pandora as seen from the Cassini probe in 2005; the rings of Saturn are in the background.

• 

  Cassini captured this close view of Saturn's moon Pandora during the spacecraft's flyby on June 3, 2010.

References

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Citations

Sources

External links

• Pandora at NASA's Solar System Exploration
• Pandora at The Planetary Society