Watch the dust shells of Wolf-Rayet 140 fade between 2022 and 2023. NASA’s Webb Space Telescope has taken incredible new images of the binary star’s dusty rings. Video via Joseph DePasquale/ Space Telescope Science Institute/ NASA/ ESA/ CSA.
- Wolf-Rayet 140 is a binary star system 5,000 light-years away. NASA’s Webb space telescope has taken stunning new images of enormous dust rings around the two stars.
- The slightly square-shaped concentric rings resemble tree rings and are rich in carbon dust. The rings are expanding outward from the stars at about 1% the speed of light.
- The spraying of carbon dust from stars like Wolf-Rayet 140 may help explain where the carbon in the universe comes from.
Binary star’s dusty rings shine in new Webb images
NASA’s Webb Space Telescope has taken some jaw-dropping images of a pair of massive stars known together as Wolf-Rayet 140. Wolf-Rayet 140 is about 5,000 light-years away. But it’s not the stars themselves that stand out, it’s the huge concentric rings – or shells – of dust expanding away from the stars. These shells look like “cosmic tree rings.” NASA said on January 13, 2025, that Webb observed 17 of the irregularly shaped shells. When stellar winds from the two stars collide, they produce the carbon-rich rings of dust. That dust may help to eventually create new stars and planets.
The researchers published the new peer-reviewed results in The Astrophysical Journal Letters on January 13, 2025. They also presented their findings at the 245th meeting of the American Astronomical Society (AAS) in National Harbor, Maryland.
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Webb observes binary star’s dusty rings
Webb observed the stars and the dust rings in infrared light. Both stars have elongated orbits, and they swing past each other every eight years. When they do so, their stellar winds collide. This produces the irregular but evenly spaced rings of dust. In infrared, the rings look slightly squarish, emanating outward from the stars. They even look like they could be artificial constructions, but in fact are just composed of carbon-rich dust. Are they even real?
Emma Lieb is the lead author of the new paper at the University of Denver in Colorado. She said:
The telescope not only confirmed that these dust shells are real, its data also showed that the dust shells are moving outward at consistent velocities, revealing visible changes over incredibly short periods of time.
Webb had also previously observed the rings back in 2022.
Fast-moving rings
Those changes are the result of the rings quickly expanding outward from the two stars. In fact, they are moving at about 1,600 miles per second (2,600 km per second), which is almost 1% the speed of light. Co-author Jennifer Hoffman at the University of Denver added:
In this system, the observatory is showing that the dust shells are expanding from one year to the next.
Each time the stars pass by each other and generate more dust, the dust can persist for several months. The rings we see now aren’t all of them, either. Some have already dissipated. And astronomers expect that thousands more will form in the future: tens of thousands over hundreds of thousands of years. The rings that Webb captured in the new images are estimated to have lasted for about 130 years.
Revealing the rings in mid-infrared light
Webb observes the universe in infrared light rather than visible light like our human eyes see. This helps it detect things that would otherwise go unseen. The rings are a great example of this. The dust in the rings is cool in temperature, so it appears more easily in mid-infrared. Co-author Ryan Lau at NSF NOIRLab in Tucson, Arizona, explained:
Mid-infrared observations are absolutely crucial for this analysis, since the dust in this system is fairly cool. Near-infrared and visible light would only show the shells that are closest to the star. With these incredible new details, the telescope is also allowing us to study exactly when the stars are forming dust, almost to the day.
The rings appear remarkably concentric and evenly spaced, although the dust isn’t completely uniform. Some of the dust piles up into delicate, amorphous clouds. And those clouds are big, some of them as large as our entire solar system. On the other hand, the dust grains themselves are extremely tiny, as small as 1/100 of a human hair. A staggering difference in scale!
Animation of the 2 binary stars in the Wolf-Rayet 140 system. When the stars swing past one another, their winds collide, material compresses, and carbon-rich dust forms. The stars create dust for several months in every 8-year orbit. Video via NASA/ ESA/ CSA/ Joseph Olmsted (STScI)/ Webb Space Telescope.
New stars and planets
The carbon these stars are spraying out can later help to form new stars and planets. But it also depends on how the stars eventually die. The Wolf-Rayet star in the binary system is about 10 times more massive than the sun. But scientists don’t know yet how its life will end. It will either explode as a supernova or collapse into a black hole.
If it explodes, it could rip apart the dust rings. But the rings would likely survive if it turned into a black hole. In that scenario, the dust could then eventually help form new stars and planets. Scientists think this is where much of the carbon in the universe comes from. As Lau noted:
A major question in astronomy is, where does all the dust in the universe come from? If carbon-rich dust like this survives, it could help us begin to answer that question.
Hoffman added:
We know carbon is necessary for the formation of rocky planets and solar systems like ours. It’s exciting to get a glimpse into how binary star systems not only create carbon-rich dust, but also propel it into our galactic neighborhood.
And carbon, of course, is essential for life, at least life as we know it.
Bottom line: NASA’s Webb Space Telescope has taken stunning new images of a binary star’s dusty rings. The rings of Wolf-Rayet 140 are expanding at 1% the speed of light.
Source: Dynamic Imprints of Colliding-wind Dust Formation from WR 140
Via Webb Space Telescope
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