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

View of Pandora's western hemisphere.
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 (sidereal)	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
Synodic rotation period	synchronous
Axial tilt	zero
Albedo	0.6
Temperature	≈ 78 K

Pandora (/pænˈdɔːrə/ 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.
• 
  View of the moon, taken during Cassini's September 2005 flyby.
• 
  Cassini captured this close view of Saturn's moon Pandora during the spacecraft's flyby on June 3, 2010.

References

Notes

Citations

Sources

• Marsden, Brian G. (October 31, 1980). "Satellites of Saturn" (discovery). IAU Circular. 3532. Retrieved 2011-12-29.
• Marsden, Brian G. (January 3, 1986). "Satellites of Saturn and Pluto" (naming the moon). IAU Circular. 4157. Retrieved 2011-12-29.
• Renner, Stéfan F.; Sicardy, Bruno; French, Richard G. (March 2005). "Prometheus and Pandora: Masses and orbital positions during the Cassini tour". Icarus. 174 (1): 230–240. Bibcode:2005Icar..174..230R. doi:10.1016/j.icarus.2004.09.005.
• "Saturn: Moons: Pandora". Solar System Exploration: Planets. NASA. 4 Apr 2011. Retrieved 2011-12-29.
• Spitale, J. N.; Jacobson, R. A.; Porco, C. C.; Owen, W. M., Jr. (2006). "The orbits of Saturn's small satellites derived from combined historic and Cassini imaging observations" (PDF). The Astronomical Journal. 132 (2): 692–710. Bibcode:2006AJ....132..692S. doi:10.1086/505206.{{cite journal}}: CS1 maint: multiple names: authors list (link)
• Thomas, P. C. (July 2010). "Sizes, shapes, and derived properties of the saturnian satellites after the Cassini nominal mission" (PDF). Icarus. 208 (1): 395–401. Bibcode:2010Icar..208..395T. doi:10.1016/j.icarus.2010.01.025. {{cite journal}}: Invalid |ref=harv (help)
• USGS/IAU (July 21, 2006). "Planet and Satellite Names and Discoverers". Gazetteer of Planetary Nomenclature. USGS Astrogeology. Retrieved 2011-12-29.

External links

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