[6] The Necklace Nebula is the exploded aftermath of a giant star that came too close to its Sun-like binary companion.

The smaller star continued orbiting inside its larger companion, increasing the giant's rotation rate.

The bloated companion star spun so fast that a large part of its gaseous envelope expanded into space.

Due to centrifugal force, most of the gas escaped along the star's equator, producing a ring.

The embedded bright knots are dense gas clumps in the ring.