Rhea (moon)

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Rhea
PIA07763 Rhea full globe5.jpg
Cassini view of Rhea's anti-Saturnian hemisphere, showing the moon's two largest impact basins (Mamaldi above and left of center, and adjacent Tirawa to its upper right). At highest resolution, several long linear features are visible: halfway down from center is Harahvaiti Fossa, while near the limb left of the bottom is Koykamou Catena.
Discovery
Discovered by G. D. Cassini
Discovery date December 23, 1672
Designations
Alternative names Saturn V
Adjective Rhean
Orbital characteristics[1]
Semi-major axis 527 108 km
Eccentricity 0.001 258 3
Orbital period 4.518 212 d
Inclination 0.345° (to Saturn's equator)
Satellite of Saturn
Physical characteristics
Dimensions 1532.4×1525.6×1524.4 km 
Mean radius 763.8 ± 1.0 km 
Surface area 7 337 000 km²
Mass (2.306 518 ± 0.000 353)×1021 kg (~3.9×10−4 Earths)
Mean density 1.236 ± 0.005 g/cm³
Equatorial surface gravity 0.265 m/s²
Escape velocity 0.635 km/s
Rotation period 4.518 212 d
(synchronous)
Axial tilt zero
Photo of Rhea taken by the Cassini-Huygens probe

Rhea (/ˈrə/;[a] Ancient Greek: Ῥέᾱ) is Saturn's second largest moon. It is made of ice and rock.

Ring system [change]

Rhea may have a thin ring system with three narrow bands in a disk of solid particles. These would be the first rings seen around a moon. The discovery was announced in the journal Science on March 6, 2008.

Notes [change]

  1. In US dictionary transcription, US dict: rē′·ə.

References [change]

  1. Natural Satellites Ephemeris Service Minor Planet Center
  2. Observatorio ARVAL (April 15, 2007). "Classic Satellites of the Solar System". Observatorio ARVAL. http://www.oarval.org/ClasSaten.htm. Retrieved 2011-12-17.