NASA’s James Webb Space Telescope has shown us images of space we’d never see otherwise, and one of the latest wonders it has captured is of an unusual star system in our galaxy with what the agency describes as “four serpentine spirals of dust.” Previous observations of the Apep system, named after the Egyptian god of chaos and located around 8,000 light-years away from Eath, showed only one shell. But as you can see in the mid-infrared image captured by Webb above, it actually has four shells, with the most outer one at the very edges of the image. These shells are made out of dense carbon dust emitted by the system’s two Wolf-Rayet stars over the last 700 years.
Wolf-Rayets are massive stars nearing the end of their lives. They’re very rare, and scientists believe there are only a thousand in our galaxy. Apep happens to have two of them. Yinuo Han from Caltech and Ryan White from the Macquarie University in Sydney, Australia have recently published their own papers about the system. They combined measurements from Webb’s observations with years of data from the European Southern Observatory’s Very Large Telescope (VLT) in Chile to determine that the two stars “swing by one another” once very 190 years. The stars then pass close to each other for 25 years, causing their strong stellar winds to collide and cast out huge amounts of carbon-rich dust within that timeframe.
Thanks to the Webb telescope’s observations, they were also able to confirm the presence of a third star in the system that’s gravitationally bound to the two Wolf-Rayets. The third star is a massive supergiant 40 to 50 times bigger than our sun, and it carved a cavity, which looks like a funnel, into the shells. You can see the cavity in the shells in the video below.
Apep’s Wolf-Rayet stars used to be bigger than the supergiant, but they’ve since shed most of their masses and are now only 10 to 20 times the mass of our sun. In time, the two stars will explode into a supernova and possibly turn into a black hole.
