Necklace Nebula

A giant cosmic necklace glows brightly in this Hubble Space Telescope image. The object, aptly named the Necklace Nebula, is a recently discovered planetary nebula, the glowing remains of an ordinary, Sun-like star. The nebula consists of a bright ring, measuring about two light-years across, dotted with dense, bright knots of gas that resemble diamonds in a necklace. The knots glow brightly due to absorption of ultraviolet light from the central stars. A pair of tightly orbiting stars produced the nebula, also called PN G054.2-03.4. The pair are so close ― only several million miles apart ― that they can only be distinguished as a single white dot in this image. The stars are furiously whirling around each other, completing an orbit in a little more than a day.