The faint ring of dust originating from Saturn’s moon Phoebe is called the Phoebe ring.
It lies far beyond Saturn’s bright main rings and is made largely of extremely fine dust and dark material blasted from Phoebe by impacts. Because Phoebe travels around Saturn in a retrograde orbit, the Phoebe ring shares that unusual backwards orbital direction. The ring is aligned broadly with Saturn’s orbit around the Sun rather than with the planet’s equatorial plane.
The Phoebe ring is extraordinarily large but exceptionally faint. Estimates place its radial extent at roughly 4 million to more than 13 million kilometers from Saturn, making it vastly broader than the familiar A, B, and C rings. Its particles are so diffuse that the ring cannot be seen like Saturn’s main rings in ordinary visible-light views.
Astronomers announced its discovery in 2009 after observations with NASA’s Spitzer Space Telescope. Later studies found that small particles dominate the ring over much of its enormous span. A common mix-up is confusing it with Saturn’s E ring, which is associated mainly with material supplied by the active icy moon Enceladus. The Phoebe ring instead points outward to the dark, distant moon Phoebe.