Saturn's Moon: Dione Rotation

Cassini named the four moons he discovered (Tethys, Dione, Rhea and Iapetus) Sidera Lodoicea ("the stars of Louis") to honour king Louis XIV. Cassini found Dione using a large aerial telescope he set up on the grounds of the Paris Observatory. The satellites of Saturn were not named until 1847, when William Herschel's son, John Herschel published Results of Astronomical Observations made at the Cape of Good Hope, and suggested the names of the Titans, sisters and brothers of Cronos (the Greek Saturn), be used.
Dione is composed primarily of water ice, but as the third densest of Saturn's moons (after Enceladus and Titan, whose density is increased by gravitational compression) it must have a considerable fraction (~ 46%) of denser material like silicate rock in its interior.
Though somewhat smaller and denser, Dione is otherwise very similar to Rhea. They both have similar albedo features and varied terrain, and both have dissimilar leading and trailing hemispheres. Dione's leading hemisphere is heavily cratered and is uniformly bright. Its trailing hemisphere, meanwhile, contains an unusual and distinctive surface feature: a network of bright ice cliffs.

Discovered by Giovanni Cassini
Discovery date 1684
Designations
Alternate name Saturn IV
Adjective Dionean
Orbital characteristics
Semi-major axis 377 396 km
Eccentricity 0.002 2[1]
Orbital period 2.736 915 d
Inclination 0.019° (to Saturn's equator)
Satellite of Saturn
Physical characteristics
Dimensions 1127.6 × 1122 × 1120.6 km
Mean radius 561.70 ± 0.45 km[3] (348.96 mi)
Mass (1.095 452 ± 0.000 168) × 1021 kg[3] (3.28 × 10−4 Earths)
Mean density 1.475 7 ± 0.003 6 g/cm³
Equatorial surface gravity 0.231 m/s2
Escape velocity 0.510 km/s
Rotation period 2.736 915 d
(synchronous)
Axial tilt zero
Albedo 0.998 ± 0.004 (geometric)
Temperature 87 K (-186°C)
Apparent magnitude 10.4

Category:

Science & Technology

Tags:

• NASA
• ESA
• Saturn moon Dione
• Dione
• Saturn
• saturn rings
• cassini spacecraft
• rings of saturn
• astronomy
• kurd
• kurdistan

[velazquezjeremy]

Muy interesante!

[TheMelanx]

El hemisferio delantero de Dione esta muy craterizado y es uniformemente brillante. Su hemisferio trasero contiene una red de líneas brillantes aunque no muy bien definidas sobre un mar de fondo oscuro. Gracias a las imágenes de mayor resolución de la sonda Cassini, ahora se sabe que estas líneas en realidad son grandes acantilados de hielo.

[TheMelanx]

Dione esta compuesto principalmente de agua congelada. Sin embargo, dado que Dione es la luna más densa de Saturno (aparte de Titán, cuya densidad es mayor por compresión gravitacional), seguramente debe tener materiales más densos en su interior, como por ejemplo rocas de silicio.

Aunque un poco más pequeña, Dione es una luna muy similar a Rea. Las dos tienen composiciones y características de albedo similares, y las dos exhiben asimetrías en sus hemisferios de adelante y atrás.