Pandora (moon)

:"There is also an asteroid called 55 Pandora." Infobox Planet
name = Pandora


caption = Pandora, as imaged by Cassini
bgcolour = #a0ffa0
discovery = yes
discoverer = Collins, Voyager 1
discovered = October, 1980
orbit_ref =cite journal | author= Spitale, J. N.; "et al."| title= "The orbits of Saturn's small satellites derived from combined historic and "Cassini" imaging observations"| journal= The Astronomical Journal| year= 2006| volume= 132 | issue=2 | pages= 692–710 | url=http://www.iop.org/EJ/article/1538-3881/132/2/692/205235.html | doi= 10.1086/505206 ]
epoch = 31 December 2003 (JD 2453005.5
semimajor = 141,720 ± 10 km
eccentricity = 0.0042
period = 0.628504213 d
inclination = 0.050 ± 0.004° to Saturn's equator
satellite_of = Saturn
physical_characteristics = yes
dimensions = 103×80×64 kmcite journal | author= Porco, C. C.; "et al."| title= "Physical Characteristics and Possible Accretionary Origins for Saturn's Small Satellites"| journal= Bulletin of the American Astronomical Society| year= 2006| volume= 37| pages= 768| url=http://www.lpi.usra.edu/meetings/lpsc2006/pdf/2289.pdf]
mean_radius = 40.3 ± 2.2 km
surface_area = ~21,000 km²
volume = ~270,000 km³
mass = 1.356 ± 0.022 e|17 kg
density = 0.49 ± 0.08 g/cm³
surface_grav = 0.0034 m/s²
escape_velocity = ~0.019 km/s
rotation = synchronous
axial_tilt = zero
albedo = 0.6
single_temperature = ~78 K

Pandora (pronEng|pænˈdɔərə respell|pan|DOHR|ə, or as in 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 nowrap|S/1980 S 26. [ [http://cfa-www.harvard.edu/iauc/03500/03532.html IAUC 3532: "Satellites of Saturn"] 1980 October 31 (discovery)] In late 1985 it was officially named after Pandora from Greek mythology. [ [http://cfa-www.harvard.edu/iauc/04100/04157.html IAUC 4157: "Satellites of Saturn and Pluto"] 1986 January 3 (naming the moon)] It is also designated as nowrap|Saturn XVII.cite web
title = Planet and Satellite Names and Discoverers
work = Gazetteer of Planetary Nomenclature
publisher = USGS Astrogeology
date = July 21, 2006
url = http://planetarynames.wr.usgs.gov/append7.html
accessdate = 2006-08-07 ]

Pandora is the outer shepherd satellite of the F Ring. It is more heavily cratered than nearby Prometheus, and has at least two large craters 30 km in diameter. [ [http://solarsystem.nasa.gov/planets/profile.cfm?Object=Sat_Pandora NASA JPL Solar System Exploration: Saturn: Moons: Pandora] ]

The orbit of Pandora appears to be chaotic, as a consequence of a mean motion resonance 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 km. 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.
Cassini probe in 2005; the rings of Saturn are in the background.

References

External links

* [http://solarsystem.nasa.gov/planets/profile.cfm?Object=Sat_Pandora Pandora Profile] by [http://solarsystem.nasa.gov NASA's Solar System Exploration]
* [http://www.planetary.org/explore/topics/saturn/pandora.html The Planetary Society: Pandora]