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Pandora (moon)

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PIA21055 - Pandora Up Close.jpg
View of Pandora's western hemisphere.[a]
Discovered byStewart A. Collins
D. Carlson
Voyager 1
Discovery dateOctober, 1980
Saturn XVII
Named after
Πανδώρα Pandōra
Orbital characteristics[2]
Epoch December 31, 2003 (JD 2453005.5)
141720±10 km
0.628504213 d
Inclination0.050°±0.004° to Saturn's equator
Satellite ofSaturn
GroupPossible outer shepherd moon of the F Ring
Physical characteristics
Dimensions104 × 81 × 64 km [3]
Mean radius
40.7±1.5 km [3]
Volume≈ 280000 km3
Mass(1.371±0.019)×1017 kg[3]
Mean density
0.49±0.06 g/cm3[3]
0.0026–0.0060 m/s2[3]
≈ 0.019 km/s
Temperature≈ 78 K

Pandora 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.[4] In late 1985 it was officially named after Pandora from Greek mythology.[5] It is also designated Saturn XVII.[6]

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.[7][8] 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.[9]

The orbit of Pandora appears to be chaotic, as a consequence of a series of four 118:121 mean-motion resonances with Prometheus.[10] The most appreciable changes in their orbits occur approximately every 6.2 years,[2] 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.[2]

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



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  1. ^ This view was taken by Cassini, during the spacecraft's close flyby on December 18, 2016. The image was taken from a distance of 40,500 kilometres (25,200 miles); the closest approach by the spacecraft during its 14-year tenure in the Saturn system.
  1. ^ Robert Kolvoord (1990) Saturn's F ring: imaging and simulation, p. 104
  2. ^ a b c Spitale Jacobson et al. 2006.
  3. ^ a b c d e Thomas 2010.
  4. ^ IAUC 3532.
  5. ^ IAUC 4157.
  6. ^ USGS: Planet and Satellite Names and Discoverers.
  7. ^ Lakdawalla, E. (2014-07-05). "On the masses and motions of mini-moons: Pandora's not a "shepherd," but Prometheus still is". Planetary Society. Retrieved 2015-04-17.
  8. ^ Cuzzi, J. N.; Whizin, A. D.; Hogan, R. C.; Dobrovolskis, A. R.; Dones, L.; Showalter, M. R.; Colwell, J. E.; Scargle, J. D. (April 2014). "Saturn's F Ring core: Calm in the midst of chaos". Icarus. 232: 157–175. Bibcode:2014Icar..232..157C. doi:10.1016/j.icarus.2013.12.027. ISSN 0019-1035.
  9. ^ Solar System, NASA: Pandora.
  10. ^ Renner et al. 2005.

External links[edit]

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