For the first time, scientists have detected radio waves from a Type Ibn supernova, revealing the final years of a massive star's life. The signals show the star shed significant material just before exploding, likely due to a companion star. This discovery offers a new method to study stellar deaths using radio telescopes.
Astronomers have achieved a milestone by detecting radio emissions from SN 2023fyq, a rare Type Ibn supernova. This type of explosion involves a massive star that releases helium-rich material shortly before tearing itself apart. The findings, detailed in a 2025 paper in The Astrophysical Journal Letters, provide unprecedented insights into the star's behavior in its last decade, particularly the intense mass loss in the final five years before the blast. The research was led by Raphael Baer-Way, a third-year Ph.D. student in astronomy at the University of Virginia. Using the National Science Foundation's Very Large Array radio telescope in New Mexico, the team monitored faint radio signals from the supernova for about 18 months. These signals indicated gas expelled only a few years prior to the explosion, details invisible to optical telescopes. Baer-Way described the technique as a 'time machine' into the star's final moments: '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.' The surrounding gas acted like a mirror, reflecting the supernova's shockwave to produce detectable radio waves. Evidence points to the star being in a binary system, where gravitational interactions with a companion triggered the extreme mass shedding. Baer-Way noted, '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.' This approach complements traditional visible-light studies and could help determine how common such dramatic pre-explosion events are. Maryam Modjaz, a professor of astronomy at UVA and supernova expert, praised the work: '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.' Future research will examine more supernovae to refine models of stellar evolution.