Posted by 
A blowtorch of seething gases erupting from a massive newborn star has been captured by NASA’s James Webb Space Telescope (JWST). Stretching an incredible 8 light-years across, the jet is nearly twice the distance between our Sun and Alpha Centauri, the closest stellar system to Earth.
This powerful outflow was discovered in the nebula Sharpless 2-284 (Sh2-284), located some 15,000 light-years away in the outer reaches of our Milky Way. According to researchers, its size and strength make it an exceptionally rare cosmic phenomenon.
A Galactic Lightsaber in Space.
The jet, streaking through space at hundreds of thousands of miles per hour, resembles a double-bladed lightsaber from Star Wars. At its core lies a protostar 10 times more massive than our Sun, still in the process of formation.
“We didn’t really know there was a massive star with this kind of super-jet out there before the observation,” explained Yu Cheng of the National Astronomical Observatory of Japan. “Such a spectacular outflow of molecular hydrogen from a massive star is rare in our galaxy.”
These protostellar jets are essentially a star’s “birth announcement” to the universe. As the infant star grows, some of the surrounding infalling gas is redirected and blasted out along its spin axis—likely driven by magnetic fields.
A Window Into Star Formation.
While astronomers have catalogued hundreds of stellar jets, most come from low-mass stars. Webb’s discovery reveals that these jets scale up with stellar mass, offering clues about how giant stars are born.
“I was really surprised at the order, symmetry, and size of the jet,” said co-author Jonathan Tan of the University of Virginia and Chalmers University of Technology. Webb’s high-resolution infrared imaging revealed a filamentary structure filled with knots, bow shocks, and linear chains—evidence that the jet is plowing into surrounding gas and dust.
Over the last 100,000 years, the jet’s opposing tips have expanded outward, leaving behind a record of the star’s formation history.
A Cosmic Outlier at the Milky Way’s Edge.
The host proto-cluster of Sh2-284 lies in the galactic outskirts, nearly twice as far from the Milky Way’s center as our Sun. This region is metal-poor, meaning it contains fewer heavy elements beyond hydrogen and helium—much like the early universe.
“Massive stars like this influence the entire evolution of galaxies,” Cheng said. “By studying Sh2-284, we gain insight into how stars formed in primitive environments billions of years ago.”
Core Accretion vs. Competitive Accretion.
For decades, scientists have debated how massive stars form. Some proposed a chaotic competitive accretion model, where gas flows in from multiple directions, causing the stellar disk and jets to wobble.
But Webb’s data tells a different story. The jets extend almost perfectly opposite each other—suggesting a stable disk, consistent with the core accretion model.
“This discovery validates predictions of core accretion,” said Tan. “It shows that even massive stars can grow steadily through ordered processes rather than chaotic ones.”
The Bigger Picture.
Where there’s one massive star, there may be others nearby. Observations from the Atacama Large Millimeter Array (ALMA) in Chile suggest the presence of another dense stellar core in Sh2-284, possibly in an earlier stage of formation.
This breakthrough, accepted for publication in The Astrophysical Journal, demonstrates how Webb is transforming our understanding of star birth, galactic evolution, and cosmic history.
Why This Matters.
- Rare Discovery – First clear evidence of a massive protostar firing an 8-light-year jet.
- Star Formation Models Tested – Supports the core accretion theory over competitive accretion.
- Clues to the Early Universe – Sh2-284’s low-metallicity environment mimics conditions billions of years ago.
- Future Insights – Could reveal how the first generations of stars shaped galaxies.
The James Webb Space Telescope continues to be humanity’s window to the origins of stars, planets, and galaxies, pushing the boundaries of cosmic exploration.