A 'Messy' Star Death: How an Early Muse of NASA's Webb Telescope Came to Be

The Southern Ring Nebula, brought to you by a star's explosive demise.

Monisha Ravisetti Former Science Writer
Monisha Ravisetti was a science writer at CNET. She covered climate change, space rockets, mathematical puzzles, dinosaur bones, black holes, supernovas, and sometimes, the drama of philosophical thought experiments. Previously, she was a science reporter with a startup publication called The Academic Times, and before that, was an immunology researcher at Weill Cornell Medical Center in New York. She graduated from New York University in 2018 with a B.A. in philosophy, physics and chemistry. When she's not at her desk, she's trying (and failing) to raise her online chess rating. Her favorite movies are Dunkirk and Marcel the Shell with Shoes On.
Monisha Ravisetti
4 min read
The Southern Ring Nebula as a whole, and views of two portions

A cosmic crime scene stands before you. Straight, brightly lit lines pierce rings of gas and dust around the edges of the Southern Ring Nebula in this highlighted James Webb Space Telescope image. A research team projects that the straight lines may have been shot out hundreds of years earlier and at greater speeds than those that appear thicker and curvy.

NASA, ESA, CSA, and O. De Marco (Macquarie University); Image processing: J. DePasquale (STScI)

When NASA released the James Webb Space Telescope's very first images this year, astronomers and space-lovers all over the world were met with a menagerie of blurred galaxies from near the beginning of time, coffee-hued dust clouds brimming with wonderful secrets and incandescent realms fit for Disney princess castles. It was a glorious moment for humankind, witnessing how stars can unite us beneath our layers of division. 

But among this trailblazing telescope's first five images, one especially stood out not only for its beauty but also for its mystery -- a striking portrait of the Southern Ring Nebula hid an important history yet to be known. Simply, scientists wanted to learn what, exactly, caused this intricate, amoeba-shaped, ancient star explosion aftermath to exist? 

Et, voila. 

On Thursday, an international team of nearly 70 astronomers used the JWST's stunning image to deduce the Southern Ring Nebula's backstory.

Details are published in the journal Nature Astronomy, but basically, what they found is that some 2,500 years ago, a star nearly three times the size of our sun died at about 500 million years of age. 

When it died, they say, the stellar body ejected most of its mass into surrounding space, forming shrouds of gas that slowly expanded with time until they turned into the complex folds we see today in the JWST's Southern Ring Nebula structure. 

Then, when all was said and done, the deceased star left behind a sort of corpse, or white dwarf star, with about half the mass of our sun but around the size of Earth. (That's super dense, to be clear). 

Plus, as an added surprise, the astronomers also found evidence of two or three companion stars they believe hastened the blown up star's death -- as well an "innocent bystander" star that might've just gotten caught up in the mix. 

"When we first saw the images, we knew we had to do something, we must investigate!" Orsola De Marco, lead author of the paper and astrophysicist at Macquarie University, said in a statement. "The community came together, and from this one image of a randomly chosen nebula, we were able to discern much more precise structures than ever before. The promise of the James Webb Space Telescope is incredible."

An infrared and near-infrared comparison of JWST's image of the Southern Ring Nebula.

NASA's Southern Ring Nebula picture, taken by the James Webb Space Telescope's Near-Infrared Imager on the left. On the right is a version taken by the JWST's Mid-Infrared imager.


That Southern Ring Nebula image really is something

Even back in July, the JWST's Southern Ring Nebula rendition had raised eyebrows during its reveal. I mean, at the top left of one version of the JWST's view, taken with the Mid-Infrared instrument, a weird bluish line ended up literally being a galaxy photobomber. 

"I made a bet that said, 'It's part of the nebula,'" NASA astronomer Karl Gordon recounted during the unveiling. "I lost the bet, because then we looked more carefully at both Nircam and MIRI images, and it's very clearly an edge-on galaxy." 

A blue streak that represents a galaxy.

See that blueish streak? A galaxy photobomber! This is from the Mid-Infrared JWST image of the Southern Ring Nebula.

Screenshot by Monisha Ravisetti/NASA

We were also able to see not one but two stars dance around one another at the marvel's center for the first time, stirring the pot of gas and dust to create the ornate patterns that make the image perfect as an iPhone background. (Yes, one of these is the white dwarf that De Marco and fellow scientists discuss in their latest paper.)

"This star is now small and hot but is surrounded by cool dust," Joel Kastner, another team member from the Rochester Institute of Technology, said in a statement. "We think all that gas and dust we see thrown all over the place must have come from that one star, but it was tossed in very specific directions by the companion stars."

Two stars, one brighter and one dying, seen in the nebular cloud.

In the Mid-Infrared rendition of the Southern Ring Nebula, you can see both stars captured together for the first time ever.

Screenshot by Monisha Ravisetti/NASA

The other star visible in the JWST's photo, according to the team, is just one of the companion stars that orbits the central star while the latter loses mass over time. 

However, as to why the team believes there aren't just two stars at play here but rather three, four – maybe more – that's because of how a series of spiral structures seem to be moving out from the center, generating arches, and how a 3D view of the nebula's data points to irregular jets of matter shooting from the phenomenon's center. 

"We first inferred the presence of a close companion because of the dusty disk around the central star, the further partner that created the arches and the super far companion that you can see in the image," De Marco said. "Once we saw the jets, we knew there had to be another star or even two involved at the center, so we believe there are one or two very close companions, an additional one at middle distance and one very far away. 

"If this is the case, there are four or even five objects involved in this messy death."