NASA’s James Webb Space Telescope (JWST) captured a remarkable image of a rare triple-star system, revealing a tightly bound two Wolf–Rayet (WR) stars wrapped in four expanding dust shells. Wolf-Rayets are a rare and extreme class of very massive, hot and luminous stars that are in a late stage of stellar evolution. These stars have extremely powerful stellar winds that strip away their outer layers, exposing the hotter helium-rich core beneath.
The discovery may hold clues into how massive stars die, and why some evolve into supernovae and the even rarer gamma-ray bursts (GRB) — ‘the most luminous explosions in the cosmos,’ according to NASA. The mid-infrared image, released on November 20, features the system named ‘Apep’ lying 8,000 light years away in the Norma constellation. It features four serpentine spiral shells, each expanding beyond the next in precisely the same pattern. The fourth shell, scientists noted, is almost transparent at the edges of Webb’s image.
Webb refined our view of Apep, a star system consisting of two rare Wolf-Rayet stars and a supermassive third star, which is slicing holes in the dusty shells its companions are creating. https://t.co/JxT8TnNPbR pic.twitter.com/fPfwrlcoOS
— NASA Webb Telescope (@NASAWebb) November 19, 2025
Prior to Webb, ground-based telescopes showed only one shell because of their limited infrared abilities. Webb has also confirmed that this system has three gravitationally bound stars (two Wolf-Rayets and one massive supergiant star). Scientists have known about the third star since 2018 but Webb proved it has a gravitational influence on the WR binary.
According to NASA, dust ejected by the two Wolf-Rayets is being slashed by this supergiant, which carves holes into each expanding cloud of dust from its wider orbit.
It is estimated that the shells were emitted by the Wolf-Rayets in the Apep system (a nod to the Egyptian god of chaos) over the last 700 years ago. Combining Webb’s data with the European Southern Observatory’s Very Large Telescope (VLT) in Chile, astronomers discovered that the Wolf-Rayet pair passed by each other once every 190 years. At some point in their orbit, they pass closely for 25 years which results in the formation of dust shells.
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‘One-of-a-kind system’
Emphasising the importance of the discovery, Ryan White, a PhD student at Macquarie University in Sydney, Australia said in a statement, “This is a one-of-a-kind system with an incredibly rare orbital period. The next longest orbit for a dusty Wolf-Rayet binary is about 30 years. Most have orbits between two and 10 years.”
The WR stars are throwing out dust at a massive scale – 1,200 to 2,000 miles per second (2,000 to 3,000 kilometers per second). NASA says their dust shell is mainly made of amorphous carbon. These dust particles retain a higher temperature even as they coast far away from the star and despite emitting faint light, they can be easily detected by Webb’s Mid-Infrared Instrument (MIRI).
Having likely shed most of their mass, the Wolf-Rayet stars are estimated to be around 10-20 times the mass of the Sun, whereas the supergiant is around 40-50 times more massive.
The Apep star system has the potential to unravel several phenomena that have long puzzled astronomers. For instance, it can help scientists understand how dust forms in the late stages of stellar evolution and eventually contribute to the formation of planets and even life. Webb’s infrared data could also reveal the chemical makeup of this dust, some of which may be similar to the building blocks of life on Earth.
This discovery is significant because there are only a thousand systems like Apep estimated to exist in the Milky Way. Moreover, Apep is the only one out of a few hundred binary systems observed to date whose both stars are Wolf-Rayets; most of them in our galaxy only contain one.
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