A new ring of Saturn has been spotted by cameras aboard the Cassini spacecraft, scientists working with the Cassini mission of the U.S. space agency NASA reported on Wednesday.

This new ring is a tenuous feature, visible outside the brighter main rings of Saturn and inside the G and E rings, and coincides with the orbits of Saturn's moons, Janus and Epimetheus.

Scientists had expected that meteoroid impacts on Janus and Epimetheus might kick particles off the moons' surfaces and inject them into Saturn's orbit, but they were surprised that a well-defined ring structure exists at this location.

The images were obtained on Sunday, Sept. 17, during the longest solar occultation, when the sun passed directly behind Saturn, and Cassini lay in the shadow of Saturn while the rings were brilliantly backlit.

Usually, an occultation lasts only about an hour, but this time it was a 12-hour marathon. It allowed Cassini to map the presence of microscopic particles that are not normally visible across the ring system, and as a result Cassini saw the entire inner Saturnian system in a new light.

Seven major rings named A through G had been identified around Saturn, but the latest discovery was unique, scientists said. The planet's extensive, diffuse E ring, is the outermost one.

The occultation on Sunday also enabled scientists to see the entire structure of the E ring in one image for the first time. The moon Enceladus was seen sweeping through the E ring, extending wispy, fingerlike projections into the ring.

These very likely consist of tiny ice particles being ejected from Enceladus' south polar geysers, and entering the E-ring.

In the coming weeks, several science teams would analyze data collected by Cassini's other instruments during this rare occultation event, according to NASA.

The data will help scientists better understand the relationship between the rings and moons, and will give mission planners a clearer picture of ring hazards to avoid during future ring crossings.

Source: Xinhua