Astronomers have detected radio waves coming from an unusually rare type of exploding star for the first time. The breakthrough gives scientists a unique way to study the final years of a massive star’s life before it ends in a violent supernova.
The results, published in The Astrophysical Journal Letterscenter on an Ibn-type supernova. This type of explosion occurs when a massive star tears itself apart after releasing a large amount of helium-rich material shortly before it dies.
Tracking the last years of stars with radio telescopes
The research team used the National Science Foundation’s Very Large Array radio telescope in New Mexico to monitor the faint radio emissions from the supernova for about 18 months. These radio signals carried clear evidence of gas ejected by the star just a few years before the explosion—information that cannot be picked up by optical telescopes alone.
Raphael Baer-Way, a third-year Ph.D. student in astronomy at the University of Virginia and lead author of the study said, “We were able to use radio observations to ‘image’ the last decade of the star’s life before the explosion. It’s like a time machine to those last important years, especially the last five, when the star was losing mass intensively.”
How escaping gas reveals hidden stellar activity
Baer-Way explained that stars in distant galaxies are usually too faint to study in detail before they explode. However, when a star ejects large amounts of material prematurely, the surrounding gas can act as a “mirror”. When a supernova shock hits this material, it creates powerful radio waves that reveal what was happening in the star’s final stages.
The observations suggest that the star was likely part of a binary system – two stars orbiting each other – and that interactions with its companion played a key role in the extreme mass loss seen just before the explosion.
“To lose the kind of mass we’ve seen in the last few years … it almost certainly requires two stars gravitationally bound together,” he explained.
A new way to study how stars die
The radio measurements not only confirm that intense mass loss can occur shortly before a supernova, but also introduce a powerful new approach to studying stellar death across the universe. Until now, scientists have relied mainly on visible light to infer these events. Radio observations now offer a complementary method that can reveal details previously hidden.
Baer-Way said the next phase of research will involve examining more supernovae to see how common these dramatic mass-loss episodes are and what they can teach scientists about how stars evolve.
“Raphael’s work has opened a new window into space for the study of these rare but crucial supernovae, as it reveals that we need to point our radio telescopes much earlier than previously thought to pick up their drifting radio signals,” said Maryam Modjaz, a professor of astronomy at UVA and an expert on massive star deaths and supernovae.
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