A cosmic “stingray” is fading away before our eyes. A recent study found that it grew much fainter and cooler in just a couple of decades — and even lost its shape.
The Stingray Nebula is about 18,000 light-years away. It’s in the constellation Ara, which is too far south to see from most of the U.S.
The nebula is the final gasp of a dying star. The star expelled its outer layers into space, forming a rapidly expanding “bubble” of gas and dust.
The Stingray is the youngest such nebula yet seen. It began forming just a few decades ago. And in 1996, an image from Hubble Space Telescope showed a bright and colorful bubble whose outline resembled that of a stingray.
But a recent study compared that picture to one taken 20 years later. And in the more recent observation, the Stingray was only a fraction as bright. It didn’t look nearly as big, and a blue-green glow at its center had vanished.
The change probably was caused by the star’s dying core. A few decades ago, a shell of helium around the core probably ignited, causing the core to flare up. The extra energy shined on the surrounding gas and dust, causing it to glow like a neon bulb.
In the more recent image, though, the flare-up had ended, and the core had grown cooler and fainter. So there wasn’t enough energy to light up the entire nebula. The nebula is still there, expanding rapidly into space. But we just can’t see the full outline of the Stingray.
Script by Damond Benningfield