Shepherd Moons is an album by Irish musician Enya, released on November 4, 1991. It won the Grammy Award for “Best New Age Album” of 1993. It was a #1 album in the UK and a Top 20 hit in the US, peaking at #17 on the Billboard 200.
A planetary ring is a ring of cosmic dust and other small particles orbiting around a planet in a flat disc-shaped region. The most notable planetary rings known in Earth’s solar system are those around Saturn, but the other three gas giants of the solar system (Jupiter, Uranus and Neptune) possess ring systems of their own.
Sometimes planetary rings will have shepherd moons, small moons that orbit near the outer edges of rings or within gaps in the rings. The gravity of shepherd moons serves to maintain a sharply defined edge to the ring; material that drifts closer to the shepherd moon’s orbit is either deflected back into the body of the ring, ejected from the system, or accreted onto the moon itself.