As anyone into astronomy likely already knows, NASA is fond of sharing incredible photos of our universe. Recently, NASA shared a stunning photo of a nebula known as the “Necklace Nebula,” which is described as “a diamond necklace of cosmic proportions.
The nebula—which also goes by its less-glamorous name, PN G054.203.4—is located roughly 15,000 light-years away from Earth near the constellation Sagitta. What we see now as the nebula was once a pair of tightly orbiting stars similar to our Sun. About 10,000 years ago, the larger star expanded and consumed the smaller one, a process scientists call a “common envelope.”
The smaller star continued to orbit while inside its larger companion, which increased their shared rotation rate causing bits of both to spin outwards. This ring of debris is what looks like the necklace, and the extra-dense groups of gas formed what looks like large diamonds around the nebula’s ring.
The two stars are still there spinning; they are the small white dot in the center of the ring. The stars are able to complete an entire orbit around each other in just over 24 hours. Hubble released a photo of this same nebula nearly a decade ago, but the new image is much better as NASA used several exposures from Hubble’s Wide Field Camera 3 and advanced processing techniques to improve it.