In a remote part of the galaxy, a giant young star is firing off two streams of hot gas in opposite directions at hundreds of thousands of miles per hour.
The star, known as S284p1, is about 10 times the mass of the sun and still growing. Its jets span roughly 8 light-years across — about double the distance between the sun and the next-closest star system. Astronomers spotted S284p1 with the James Webb Space Telescope, a joint partnership of NASA and its European and Canadian counterparts.
Though hundreds of baby stars’ beams — aka “protostellar jets” — have been seen before, they’re mainly powered by small stars. Observing such large jets coming from an enormous star is rare and suggests the scale of the jet correlates with the size of the developing star, scientists said.
The discovery provides new insight into how giant stars take shape — and how similar processes may have worked in the early universe. The new findings have been accepted for publication in The Astrophysical Journal.
“We didn’t really know there was a massive star with this kind of super-jet out there before the observation,” said Yu Cheng, lead author of the paper, in a statement. “Such a spectacular outflow of molecular hydrogen from a massive star is rare in other regions of our galaxy.”
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The new observations may mean that these stars can grow in calm and orderly ways, even in harsh conditions.
Credit: NASA GSFC / CIL / Adriana Manrique Gutierrez illustration
S284p1 sits at the edge of the Milky Way about 15,000 light-years from Earth. As superheated gas falls onto the star, it gets redirected as narrow beams, confined by powerful magnetic fields. The jets shoot outward — 180 degrees apart — into surrounding dust and gas.
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Not only are the jets surprising, but the star’s location adds to the intrigue. S284p1 lies in Sharpless 2-284, a region brimming with dense gas clouds and clusters of young stars. But the area contains few elements heavier than hydrogen and helium. Many scientists had predicted that giant stars developing in this environment would form in a sloppy manner because heavier elements help gas cool and clump together.
That doesn’t seem to have held back this star.
“I was really surprised at the order, symmetry, and size of the jet when we first looked at it,” said Jonathan Tan, a co-author from the University of Virginia and Chalmers University of Technology, in a statement.
Scientists didn’t expect to find such signs of smooth star formation: Heavier elements are known to be instrumental to the process, helping gas cool, break apart, and collapse. In the absence of those materials, experts have thought the process should look much different, perhaps happening in sporadic bursts. The new observations may mean that these stars can grow in calm and orderly ways, even in harsh conditions.
Most of the chemicals in the universe come from exploded stars, so scientists have long thought that the very first stars were made almost entirely of hydrogen and helium, the primitive material that emerged from the Big Bang.
Over time, as stars died, they blasted out heavier elements, which astronomers refer to as “metals.” Those supernova dispersals seed new generations of stars and planets, but scientists admit they still have much to learn about how it works.
Massive stars like S284p1 have important influences on the evolution of galaxies that scientists want to better understand, said Cheng, who works for the National Astronomical Observatory of Japan.
“We can use this massive star as a laboratory to study what was going on in earlier cosmic history,” Cheng said.