Enceladus is Supplying Ice to Saturn’s A-Ring

by Fraser Cain on February 5, 2008

One of the biggest discoveries made by Cassini is at Saturn’s moon Enceladus, where great plumes of icy material were seen spewing from its southern pole. Now scientists think that this material is traveling all the way inward to get trapped into Saturn’s A-ring.

Scientists had already linked together Saturn’s E-ring with the material spewed out by Enceladus. And researchers had worked out that the whole magnetic environment around Saturn is weighed down by the Enceladus material, which becomes plasma.

But now this.

“Saturn’s A-ring and Enceladus are separated by 100,000 kilometers (62,000 miles), yet there’s a physical connection between the two,” says Dr. William Farrell of NASA’s Goddard Space Flight Center in Greenbelt, Md. “Prior to Cassini, it was believed that the two bodies were separate and distinct entities, but Cassini’s unique observations indicate that Enceladus is actually delivering a portion of its mass directly to the outer edge of the A-ring.” Farrell is lead author of a paper on this Saturn discovery that appeared in Geophysical Research Letters January 23.

The gas particles are ejected from Enceladus and then become electrically charged by sunlight and through interactions with other particles. Once they’re charged, the particles can come under the sway of Saturn’s magnetic field, which traps and directs them around. The particles can move around from pole to pole, but once they enter Saturn’s A-ring, they’re stuck there for good.

Scientists had actually predicted this in the early 1990s. Using the Hubble Space Telescope, they saw a large presence of water-related molecules in orbit around Saturn. The researchers modeled the motions of this icy material, and calculated that it could migrate all the way in to the A-ring. But the source of this water cloud was unknown.

This discovery backs up the prediction, and provides a source for the cloud of water-related molecules feeding into the A-ring.

They’re coming from Enceladus.

Original Source: NASA News Release


Fraser Cain is the publisher of Universe Today. He's also the co-host of Astronomy Cast with Dr. Pamela Gay.

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