Pan

Saturn XVIII

Pan is the innermost of Saturn's known satellites:

        orbit:    133,583 km from Saturn
        diameter: 20 km
        mass:     ?

Pan was the god of woods, fields, and flocks, having a human torso and head with a goat's legs, horns, and ears.

Discovered by Mark R. Showalter in 1990 from Voyager photos. Recovered 24 years later in Cassini images.

Pan is within the Encke Division in Saturn's A ring.

Small moons near the rings produce wave patterns in the rings. Prior to the discovery of Pan, an analysis of the patterns in the edge of Saturn's A ring predicted the size and location of a small moon. Pan was discovered by reexamining the 10 year old Voyager photos at the predicted spot.

It is possible that there are more moons within Saturn's rings yet to be discovered.

More about Pan

• more images
• 1990 NASA press release about the discovery of Pan

Atlas

Saturn XV

Atlas is the second of Saturn's known satellites:

        orbit:    137,670 km from Saturn
        diameter: 30 km (40 x 20)
        mass:     ?

Atlas was a Titan condemned by Zeus to support the heavens upon his shoulders; son of Iapetus and the nymph Clymene; brother of Prometheus and Epimetheus.

Discovered by R. Terrile in 1980 from Voyager photos.

Atlas seems to be a shepherd satellite of the A ring.

More about Atlas

• from TPS

Open Issues

• What role do these moons play with respect to the rings?
• We know next to nothing about these moons. Even the basic mass and size data are not very accurate.
• Are Pan and Atlas similar to Prometheus in bulk properties?

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