Pandora (moon)

Pandora

View of Pandora's western hemisphere.[lower-alpha 1]
Discovery
Discovered by Collins, Voyager 1
Discovery date October, 1980
Orbital characteristics [1]
Epoch December 31, 2003 (JD 2453005.5)
141720±10 km
Eccentricity 0.0042
0.628504213 d
Inclination 0.050°±0.004° to Saturn's equator
Satellite of Saturn
Physical characteristics
Dimensions 104 × 81 × 64 km [2]
Mean radius
 40.7±1.5 km [2]
Volume ≈ 280000 km3
Mass (1.371±0.019)×1017 kg[2]
Mean density
 0.49±0.06 g/cm3[2]
0.0026–0.0060 m/s2 [2]
≈ 0.019 km/s
synchronous
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.[3] In late 1985 it was officially named after Pandora from Greek mythology.[4] It is also designated as Saturn XVII.[5]

    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.[6][7] 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.[8]

    The orbit of Pandora appears to be chaotic, as a consequence of a series of four 118:121 mean-motion resonances with Prometheus.[9] The most appreciable changes in their orbits occur approximately every 6.2 years,[1] 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.[1]

    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.

    References

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    Notes
    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.
    Citations
    1. 1 2 3 Spitale Jacobson et al. 2006.
    2. 1 2 3 4 5 Thomas 2010.
    3. ↑ IAUC 3532.
    4. ↑ IAUC 4157.
    5. ↑ USGS: Planet and Satellite Names and Discoverers.
    6. ↑ 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.
    7. ↑ 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. ISSN 0019-1035. doi:10.1016/j.icarus.2013.12.027.
    8. ↑ Solar System, NASA: Pandora.
    9. ↑ Renner et al. 2005.
    Sources
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