BALTIMORE, Aug. 11 (UPI) -- A newly released image from the Hubble Space Telescope shows a recently discovered planetary nebula dubbed the Necklace Nebula, U.S. astronomers said.
The nebula is the glowing remains of an ordinary sun-like star, in a ring 12 trillion miles across with dense, bright knots of gas that resemble diamonds in a necklace, a release from the Space Telescope Science Institute said Thursday.
The nebula, located 15,000 light-years away in the constellation Sagitta, was imaged on July 2 by Hubble's Wide Field Camera showing the glow of hydrogen (blue), oxygen (green), and nitrogen (red).
The glowing colors of the knots are due to absorption of ultraviolet light from the nebula's central stars.
Astronomers said a pair of stars orbiting very close together produced the nebula about 10,000 years ago when one of the aging stars ballooned to the point where it enveloped its companion star, causing the larger star to spin so fast much of its gaseous envelope expanded into space producing a dense ring.
The stars are still furiously whirling around each other, the scientists said, completing an orbit in a little more than a day.
