Fading Stingray Nebula Highlighted In Hubble Picture

There's all sorts of beauty found in the universe, and many of the most beautiful images were captured by the Hubble Space Telescope. NASA recently used Hubble photographs to highlight a fading nebula officially named Hen 3-1357and nicknamed the Stingray Nebula. Hubble imaged the Stingray Nebula multiple times over the years, and NASA has shared a photograph highlighting how the nebula is fading.

In the image above, the nebula is seen as very bright in 1996, and the second image from 2016 shows how, in a decade, the nebula faded significantly. Researchers say that witnessing such a fast change in a planetary nebula is exceedingly rare. NASA scientists note that the two images show the nebula drastically dimmed in brightness and has changed shape. The bright blue tendrils of gas toward the center of the nebula seen in 1996 are all but gone.

In 1996 the wavy edges earned the nebula its name; by 2016, they were almost nonexistent. Researchers have found significant changes in the light emitted by the glowing nitrogen, hydrogen, and oxygen being blasted away from the dying star at the center of the nebula. Significant changes were particularly noted in oxygen emissions, which dropped in brightness by a factor of nearly 1000 between 1996 and 2016.

Researcher Bruce Balick from the University of Washington, Seattle, lead researcher on this project, and said that changes in nebulae have been seen before. Still, in this instance, scientists have witnessed changes in the fundamental structure of the nebula. Balick notes that in most studies, the nebula gets bigger, but in this instance, it's fundamentally changing its shape and getting fainter in an unprecedented timescale.

Interestingly, the nebula isn't getting larger, and the once-bright center elliptical ring appears to be shrinking as it fades. Ground-based telescopes have been observing the nebula and have discovered hints that it's changing in brightness over time, but that speculation was only confirmed now using Hubble. The rapid changes are in response to the central star, the nebula, SAO 244567, expanding due to a temperature drop and emitting less ionizing radiation.

Past observation showed that the star's temperature increased from less than 40,000 degrees to 108,000 degrees Fahrenheit between 1971 in 2002. In the years since then, the star appears to be falling back into its early stages of stellar evolution.