Astronomers may have found the remains of two long-dead stellar siblings
By Sam Macdonald edited by Claire Cameron
This composite of radio, infrared, optical and ultraviolet data shows the region around IC 443, a famous supernova remnant also known as the Jellyfish Nebula.
NASA Goddard Space Flight Center/Mr. Michailidis et al. 2026; DSS (DSSoptical); MWSIP/ESA/Planck (radio); NASA/WISE/JPL-Caltech/UCLA (infrared); NASA/Swift (ultraviolet); SSR/eROSITA (x-ray)
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Millions of years ago, two massive stars orbited each other in a cosmic dance. Then one of the stars left supernova. The explosion likely threw the exploded star’s companion through space, leaving it adrift in the cosmos for tens of thousands of years before it also succumbed to the same explosive end.
At least that’s what astronomers think happened to a pair of newly identified stellar remnants. Using observations from NASA’s Fermi Gamma-ray Space Telescope, researchers suggest that two clouds of supernova debris were once part of a binary star system: a pair of stars bound together by gravity and orbiting a common center.
“There are so many striking connections between the two remains,” said Miltiadis Michailidis, a postdoctoral researcher in the physics department at Stanford University. in a statement. “They are likely related, giving us the first known example of a binary system in which both stars underwent supernova explosions.”
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When a star explodesit expels powerful shock waves that can accelerate charged particles to near-light speeds, creating cosmic rays. As these cosmic rays strike nearby gas cloudsthey produce gamma rays, the most energetic form of light. By detecting these gamma rays, astronomers can trace the lingering remains of ancient supernovae long after the original stars have disappeared.
This multi-wavelength scene shows the remnant of the Jellyfish Nebula supernova (RIGHT), the interstellar cloud it interacts with and a distinctive curved filament at upper left.
NASA Goddard Space Flight Center/Mr. Michailidis et al. 2026; DSS (DSSoptical); NASA/WISE/JPL-Caltech/UCLA (infrared); NASA/Swift (ultraviolet)
Using 16 years of Fermi observations, researchers examined two remnants of the Gemini constellation: the famous Jellyfish Nebula (IC 443) and a much weaker neighbor called G189.6+3.3. Both remnants appear to interact with the same dense gas clouds. Computer simulations further confirmed the observations. Combined with estimates placing the objects at roughly the same distance from Earth, the data suggests that the two remains share not only a neighborhood but potentially a common origin.
The researchers also calculated that the chances that the observed alignment occurred by chance are less than 1 percent. “We can now connect the bright remnants of two massive stars to a powerful pair that evolved together for thousands of years,” Elizabeth Hays, a Fermi project scientist at NASA’s Goddard Space Flight Center in Greenbelt, Maryland, said in the same release.
If confirmed, the interaction between the Jellyfish Nebula and G189.6+3.3 would provide a rare target for studying how massive binary stars evolve and die. The discovery could also help astronomers better understand the origin of some of the most energetic particles in the universe.
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