Saturn’s Phoebe ring just offered astronomers new exciting findings regarding its size, composition and possible clues as to its formation.
The star of the new study is the outermost ring of Saturn, surrounding one of its moons, Phoebe. That is where is takes its name from as well. The exciting finding consists of proof that the Phoebe ring has been around for much longer than previously thought, as well as of considerable larger proportions and closer to Saturn than previous research suggested.
The Phoebe ring is now known to be the largest ring of Saturn, even for a planet its size. It is 270 time the giant planet’s size, and as a fun fact that could help anyone approximate, Saturn is approximately 75,000 miles in diameter.
Under normal conditions, Phoebe ring is invisible. That is precisely why the researchers are so worked up about having been able to capture a photo of the ring in its entirety. Since its discovery in 2009, this marks the moment when the most is known about the mysterious Phoebe ring.
The enormous ring is composed of dust particles and is now known to have an inner edge located approximately 3.7 million miles from Saturn while reaching out for another 6.4 million miles. In thickness Phoebe ring measures 1.6 million miles.
The dust particles that make up Phoebe ring are as small as 10 millionths of one meter. Due to their size the sunlight radiation pressure them inwards toward Saturn’s other moon, Iapetus, creating the phenomenon labelled as ‘black rain from Phoebe’ according to Douglas Hamilton from the University of Maryland.
Thanks to this piece of knowledge and taking into account that Saturn has Iapetus tidally locked in its orbit, the study indicates that Phoebe ring dust particles set on the leading hemisphere of Iapetus. This led to a heating of the hemisphere, thus exposing darker material that lies underneath the icy surface of Iapetus.
These findings are extremely relevant for understanding what could have been the composition when the giant Saturn appeared. Understanding the dust particle distribution from the Phoebe ring and combining this with the distribution of Saturn’s moons is crucial to the effort.
While today the Phoebe ring is almost invisible, researchers believe that in the past, when satellites and orbits around Saturn collided, the Ring would have appeared both brighter and denser.
The research team pooled data from NASA’s WISE craft.
Image Source: wired.com