As from a rare kind of stellar explosion known as a Type Ibn supernova, giving them an unusually detailed look at the final decade in the life of a massive star before it died. The observations capture how the star shed large amounts of helium-rich gas shortly before it exploded, providing a record of its late-stage evolution.
The research team used the National Science Foundation's Very L Charlottesville VA (SPX) Jan 30, 2026
As from a rare kind of stellar explosion known as a Type Ibn supernova, giving them an unusually detailed look at the final decade in the life of a massive star before it died. The observations capture how the star shed large amounts of helium-rich gas shortly before it exploded, providing a record of its late-stage evolution.
The research team used the National Science Foundation's Very Large Array radio telescope in New Mexico to monitor faint radio emission from the supernova for about 18 months after the explosion. By tracking how the radio signal changed over time, they were able to reconstruct when and how much material the star expelled into space in the years leading up to its death.
Type Ibn supernovae occur when a massive star explodes into a dense envelope of helium-rich gas that it had already thrown off. When the supernova's shockwave plows into this gas, the interaction produces strong radio waves that carry information about the star's mass-loss history. In this case, the radio data revealed patterns that could not be seen with optical telescopes alone.
Lead author Raphael Baer-Way, a third-year Ph.D. student in astronomy at the University of Virginia, said the radio measurements effectively let astronomers look back in time over the last decade of the star's life. He described the surrounding gas as a kind of mirror that records the star's final activity and becomes visible when the explosion's shockwave slams into it.
The study indicates that the progenitor star likely belonged to a binary system, with two stars orbiting each other. The researchers conclude that gravitational interaction with a companion star probably drove the intense mass loss during the last few years before the explosion.
Baer-Way said the amount of mass inferred from the radio data is difficult to explain with a single isolated star. He argued that the scale and rapid timing of the mass loss are best accounted for when a companion star alters the structure and evolution of its partner late in life.
The new work shows that radio observations provide a powerful tool for probing the deaths of massive stars across the universe. Until now, most studies of such events have relied heavily on optical light, which does not always reveal the detailed history of mass loss in the years just before a supernova.
According to the team, systematically observing more supernovae in radio could show how common these intense mass-loss episodes are and how they shape the diversity of stellar explosions. A larger sample would also help clarify what kinds of stars produce Type Ibn events and how binary interaction influences their final fates.
Study co-author Maryam Modjaz, a professor of astronomy at the University of Virginia and an expert on massive star death and supernovae, said the work demonstrates the need to point radio telescopes at these rare explosions earlier than previously assumed. She noted that the signals can be brief, so rapid follow-up is essential to catch the crucial phases when the shockwave first encounters the nearby gas.
The findings are reported in The Astrophysical Journal Letters in a paper titled "The First Radio View of a Type Ibn Supernova in SN 2023fyq: Understanding the Mass-loss History in the Last Decade before the Explosion." The authors say their results set the stage for future campaigns that will link radio, optical, and other wavelengths to build a more complete picture of how massive stars live and die.
Research Report:The First Radio View of a Type Ibn Supernova in SN 2023fyq: Understanding the Mass-loss History in the Last Decade before the Explosion
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