NASA's Webb Telescope Reveals Long-Studied Star Is Actually A Twin

NASA's Jet Propulsion Laboratory managed Webb's Mid-Infrared Instrument (MIRI) through its launch, which also revealed jets of gas flowing into space from the twin stars.

Scientists received a major surprise from NASA's James Webb Space Telescope when they directed it towards a group of young stars known as WL 20. Although the region has been studied since the 1970s with at least five telescopes, it took Webb's unparalleled resolution and specialized instruments to uncover that what researchers had long thought was a single star, WL 20S, is a pair that formed about 2 million to 4 million years ago, NASA said in a press release. 

This discovery, made using Webb's MIRI, was presented at the 244th meeting of the American Astronomical Society on June 12. MIRI also revealed that the twin stars have matching jets of gas streaming into space from their north and south poles.

"Our jaws dropped," said astronomer Mary Barsony, lead author of a new paper describing the results. "After studying this source for decades, we thought we knew it pretty well. But without MIRI we would not have known this was two stars or that these jets existed. That's really astonishing. It's like having brand new eyes."

The team received another surprise when additional observations by the Atacama Large Millimeter/submillimeter Array (ALMA), a collection of over 60 radio antennas in Chile, revealed that disks of dust and gas encircle both stars. Given the stars' age, planets may be forming within these disks.

The combined findings suggest that the twin stars are approaching the end of this early stage in their development, providing scientists with an opportunity to learn more about how stars transition from youth to adulthood.

"The power of these two telescopes together is really incredible," said Mike Ressler, project scientist for MIRI at NASA's Jet Propulsion Laboratory and co-author of the new study. "If we hadn't seen that these were two stars, the ALMA results might have just looked like a single disk with a gap in the middle. Instead, we have new data about two stars that are clearly at a critical point in their lives, when the processes that formed them are petering out."