BERKELEY, July 6 -- The problem with superluminous supernovae has always been the brightness. These stellar explosions shine ten or more times brighter than ordinary supernovae and persist for months when a typical dying star fades in weeks, and the energy budget required to explain that excess pointed for years toward a theoretical object at their core. On Monday, a paper published in Nature confirmed what that object is. The signal that settled the argument was a four-beat chirp in the fading light of a star one billion light-years from Earth.

The star is designated SN 2024afav, detected in December 2024. About 50 days after it reached peak brightness, the team led by Joseph Farah, a graduate student at UC Santa Barbara and Las Cumbres...