Feature | May 10, 2017

A Bright Arc in Saturn's G Ring

The arc in Saturn’s G ring orbits at a distance of 104,080 miles (167,496 kilometers) from the planet. It is about 155 miles (250 kilometers) wide. The classical position of the G ring is about 107,250 miles (172,600 kilometers) from Saturn. Scientists suspect that bodies trapped in this remarkably bright feature, which includes the small moon Aegaeon, may be the source of the G ring material, driven outward from the arc by electromagnetic forces in the Saturn system.

The arc itself is likely held in place by gravitational resonances with Saturn’s moon Mimas of the type that anchor the famed arcs in Neptune's rings.

In 2006, a movie sequenced Saturn's G ring over a full orbital revolution and captured its single bright arc on the ring's inner edge.

The images in this movie were taken on Sept. 19 and 20 at a distance of approximately 2.1 to 2.2 million kilometers (1.3 to 1.4 million miles) from Saturn and at a Sun-G ring-spacecraft, or phase, angle that ranged from 167 to 164 degrees. Image scale is about 13 kilometers (8 miles) per pixel in the radial (outward from Saturn) direction.