Saturns rings are painting its innermost moons.
Data from NASAs now-defunct Cassini spacecraft show that five odd-shaped moons embedded in Saturns rings are different colors, and that the hues come from the rings themselves, researchers report. That observation could help scientists figure out how the moons were born.
“The ring moons and the rings themselves are kind of one and the same,” says planetary scientist Bonnie Buratti of NASAs Jet Propulsion Laboratory in Pasadena, Calif. “For as long as the moons have existed, theyve been accreting particles from the rings.”
Saturn has more than 60 moons, but those nearest to the planet interact closely with its main band of rings. Between December 2016 and April 2017, Cassini passed close to five of these ring-dwelling moons: ravioli-shaped Pan and Atlas (SN Online: 3/10/17), ring-sculpting Daphnis and Pandora (SN: 9/2/17, p. 16) and potato-shaped Epimetheus. The flybys brought Cassini between two and 10 times closer to the moons than it had ever been, before the spacecraft deliberately crashed into Saturn in September 2017 (SN Online: 9/15/17).
Examining those close-ups, Buratti and her colleagues noticed that the moons colors vary depending on the objects distances from Saturn. And the moon hues are similar to the colors of the rings that the objects are closest to, the team reports online March 27 in Science.
Cassinis last flybys of five of Saturns ring-dwelling moons — including Pan, Daphnis and Epimetheus (below in gray-scale images) — showed that their colors varied with distance from the planet. That suggests theyre picking up ring debris, scientists say.
Close-in Pan was the reddest moon, while the farthest-out Epimetheus was the bluest. The researchers think the red material comes from Saturns dense main rings, and mostly consists of organics and iron (SN Online: 10/4/18). The blue material is probably water ice from Saturns more distant E ring, which is created by plumes erupting from the larger, icy moon Enceladus.
The team thinks that the rings are continually depositing material onto the moons. “IRead More – Source