A spectacular stellar jet has been captured by NASA’s James Webb Space Telescope, showcasing a blowtorch of seething gases erupting from a volcanically growing monster star. This remarkable phenomenon, stretching across an impressive 8 light-years, is located in a nebula known as Sharpless 2-284 (Sh2-284) and measures approximately twice the distance between our Sun and the Alpha Centauri system, the nearest star system to our own.
The sheer size and strength of this stellar jet qualify it as an exceptionally rare find, according to researchers. The outflow, which streaks across space at hundreds of thousands of miles per hour, resembles a double-bladed dueling lightsaber from the iconic Star Wars films. At the center of this stellar spectacle is a protostar that weighs as much as ten Suns and is located an astounding 15,000 light-years away in the outer reaches of our Milky Way galaxy. Lead author Yu Cheng from the National Astronomical Observatory of Japan expressed surprise at the discovery, stating, “We didn’t really know there was a massive star with this kind of super-jet out there before the observation.”
This unique class of stellar fireworks consists of highly collimated jets of plasma shooting out from newly forming stars, serving as a spectacular “birth announcement” to the universe. As gas accumulates around the central star, some of it is blasted along the star’s spin axis, likely influenced by powerful magnetic fields. Although hundreds of protostellar jets have been observed, most originate from low-mass stars. These jets provide crucial clues into the nature of star formation, with their energetics, narrowness, and evolutionary time scales helping to constrain models of the environments and physical properties of the young stars powering them.
The detailed filamentary structure of the jet, captured in stunning resolution by Webb’s infrared capabilities, is indicative of its interaction with interstellar dust and gas. This interaction creates separate knots, bow shocks, and linear chains along the jet’s path. The tips of the jet, which are extending in opposite directions, encapsulate the star’s formation history. Co-author Jonathan Tan from the University of Virginia noted, “Originally the material was close into the star, but over 100,000 years, the tips were propagating out, and then the stuff behind is a younger outflow.”
Located nearly twice as far from the galactic center as our Sun, the host proto-cluster of this voracious jet lies on the outskirts of the Milky Way. The cluster contains a few hundred stars still in the formation process. Due to its position in the galactic hinterlands, these stars are deficient in heavier elements beyond hydrogen and helium—an aspect referred to as metallicity. This low metallicity reflects the cluster's relatively pristine nature, making it a valuable analog for environments in the early universe, which also lacked heavier elements.
Cheng emphasized the importance of massive stars in galaxy evolution, stating, “Our discovery is shedding light on the formation mechanism of massive stars in low metallicity environments, allowing us to use this massive star as a laboratory to study earlier cosmic history.”
The dynamics of stellar jets, powered by the gravitational energy released as a star gains mass, encode the formation history of the protostar. Tan remarked on the findings, “Webb’s new images indicate that the formation of massive stars in such environments could proceed via a relatively stable disk around the star, aligning with theoretical models of star formation known as core accretion.” This insight allows astronomers to develop new theoretical core accretion models that help describe the mass and growth of the central star, estimated to be about ten times the mass of the Sun.
For over three decades, scientists have debated the process of massive star formation. Some theories suggest that massive stars emerge from chaotic processes, where material falls in from multiple directions, altering the orientation of the disk. However, the observations from Webb reveal a nearly symmetrical structure, indicating a stable central disk and validating predictions made by core accretion theory. “What we’ve seen here, because we’ve got the whole history – a tapestry of the story – is that the opposite sides of the jets are nearly 180 degrees apart from each other,” Tan explained.
As researchers continue to explore this outer frontier of the Milky Way, it’s possible that other massive stars are in the early stages of formation, yet to release their own spectacular outflows. Data from the Atacama Large Millimeter Array (ALMA) in Chile has identified another dense stellar core that may be in a preliminary construction phase.
The groundbreaking discoveries made by the James Webb Space Telescope mark it as the world’s premier space science observatory. Webb's capabilities are helping to solve mysteries within our solar system, investigate distant worlds around other stars, and probe the intricate structures and origins of our universe. Webb is an international program led by NASA in collaboration with the European Space Agency (ESA) and the Canadian Space Agency (CSA).
To learn more about the James Webb Space Telescope and its findings, visit NASA's official website.
