Astronomers Make First Radio Detection of Rare Supernova Type, Revealing Secrets of Stellar Death

Astronomers using the U.S. National Science Foundation Very Large Array (NSF VLA)  have made an unprecedented discovery, capturing the first-ever radio signals from a rare class of stellar explosion known as a Type Ibn supernova. This achievement brings fresh insight into the death throes of massive stars and provides a rare glimpse into the final years of a star’s life, previously hidden from view.

The supernova, designated SN 2023fyq, represents a unique opportunity to observe a massive star’s final act. Type Ibn supernovae result when a star explodes into helium-rich gas previously ejected from its surface. Using the NSF VLA’s powerful radio vision, astronomers tracked radio emissions from this explosion over a span of 18 months, uncovering compelling evidence about the environment around the dying star.

“We captured a rare, first-ever radio signal from a star exploding into helium-rich gas it shed shortly before the blast,” said Raphael Baer-Way, a graduate student at UVA working with Maryam Modjaz (UVA) and Poonam Chandra (NRAO) and primary investigator on the study. “Radio observations allowed us to ‘view’ the final decade of the star’s life before the demise. These observations revealed the star shedding its helium layers, including a significant five-year surge in mass loss immediately preceding the supernova, providing fresh evidence for binary-driven, exotic explosions.” This discovery reveals that the star underwent a dramatic period of mass loss, likely caused by the influence of a gravitationally bound stellar companion.

Radio and X-ray data revealed the density and extent of the helium-rich material ejected before the explosion. Astronomers determined that the star shed material at an astonishing rate — up to 0.4% of the mass of the sun per year — during a short-lived but intense phase leading up to the supernova explosion. This dynamic process aligns with predictions for stars in close binary systems and gives astrophysicists new, direct evidence of the mechanisms driving such rare supernovae.

Until now, the existence of dense material around most Type Ibn supernovae had only been inferred from optical studies. Dr. A.J. Nayana at UC Berkeley, a co-lead investigator, says “Our study probes the material ejected years before the explosion – revealing that the star underwent an intense phase of mass-loss in the final 0.7–3 years of its life.” By pinpointing the timeframe and magnitude of the mass loss, astronomers have filled a crucial gap in the story of how massive stars end their lives and enrich the Universe.

This landmark detection sets the stage for future studies of supernovae with radio telescopes, promising to deepen our understanding of the life cycles of stars and the forces that shape our galaxy. Dr. Wynn Jacobson-Galan at Caltech, another lead investigator and VLA program PI, says, “this study has opened up a whole new avenue for constraining the end points of certain massive stars and really highlights the need for systematic radio follow-up of similar events with incredible instruments like the VLA and GMRT.”

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This news article was originally published on the NRAO website on December 12, 2025.