Atlas, as imaged by Cassini on June 8, 2005.
Atlas, as imaged by Cassini on June 12, 2007, from over the moon's south pole.
Atlas orbits near the outer edge of the A-ring (see Saturn's rings) and it was originally suspected of acting as a shepherd moon for this ring. However, it is now known that the outer edge of the A-ring is kept sharp due to a 7:6 orbital resonance with the larger but more distant moons Janus and Epimetheus.
Images taken by the Cassini spacecraft have shown that Atlas has very prominent equatorial ridge, which makes the moon saucer-shaped. The most likely cause of this structure is ring material that has been swept up by the moon as it travels around its orbit.
|discovery||1980, by R. Terrile/Voyager 1|
|semimajor axis||137,670 km (85,560 mi)|
|diameter||46 × 38 × 19 km (29 × 24 × 12 mi)|
|orbital period||0.602 day (14 h 27 min)|
The star Atlas, or 27 Tauri, is the second brightest star in the Pleiades, with a visual magnitude of 3.63, is also known as Atlas.
The Atlas rocket is an important launch vehicle in America's space program.