Radio waves revealed what happened before a star exploded
· ScienceDaily| Source: | University of Virginia College and Graduate School of Arts & Sciences |
| Summary: | For the first time, astronomers have captured radio signals from a rare exploding star, exposing what happened in the years leading up to its death. The radio waves reveal that the star violently shed huge amounts of material shortly before it exploded, likely due to interaction with a nearby companion star. This discovery gives scientists a new tool to rewind the clock on stellar deaths. It also shows that some supernovae are far more dramatic in their final moments than previously thought. |
Astronomers have, for the first time, detected radio waves coming from an unusually rare kind of exploding star. This breakthrough gives scientists a unique way to examine the final years of a massive star's life before it ends in a violent supernova.
The results, published in The Astrophysical Journal Letters, center on a Type Ibn supernova. This type of explosion occurs when a massive star tears itself apart after releasing large amounts of helium-rich material shortly before it dies.
Tracking a Star's Final Years With Radio Telescopes
The research team used the National Science Foundation's Very Large Array radio telescope in New Mexico to follow faint radio emissions from the supernova for about 18 months. These radio signals carried clear evidence of gas that the star expelled only a few years before the explosion — information that cannot be captured with optical telescopes alone.
Raphael Baer-Way, a third-year Ph.D. student in astronomy at the University of Virginia and the study's lead author, said, "We were able to use radio observations to 'view' the final decade of the star's life before the explosion. It's like a time machine into those last important years, especially the final five when the star was losing mass intensely."
How Escaping Gas Reveals Hidden Stellar Activity
Baer-Way explained that stars in distant galaxies are typically too faint to study in detail before they explode. However, when a star releases a large amount of material ahead of time, that surrounding gas can act as a "mirror." When the supernova's shockwave slams into this material, it produces strong radio waves that reveal what was happening in the star's final stages.
The observations suggest 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 saw in just the last few years… it almost certainly requires two stars gravitationally bound to each other," he explained.
A New Way to Study How Stars Die
The radio measurements not only confirm that intense mass shedding can happen shortly before a supernova, but also introduce a powerful new approach for 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 from view.
Baer-Way said the next phase of research will involve examining a larger number of supernovae to determine how common these dramatic mass-loss episodes are and what they can teach scientists about how stars evolve.
"Raphael's paper has opened a new window to the Universe for studying these rare, but crucial Supernovae, by revealing that we must point our radio telescopes much earlier than previously assumed to capture their fleeting radio signals," said Maryam Modjaz, professor of astronomy at UVA and an expert on massive star death and supernovae.