A division in Saturn's rings, very close to the outer edge of the A Ring. It lies 136 530 km from Saturn's centre and is between 32 and 47 km wide. Its boundaries are not circular, and show radial wave-like variations as a result of resonances with the moon Prometheus which orbits just outside the A Ring. Its existence was confirmed by the Voyager probes; it is named after the American astronomer James Edward Keeler (1857–1900), who saw it in 1888.
Subjects: Astronomy and Astrophysics.