Astronomers catch a magnetar being born inside a supernova via a rapid brightness chirp
Astronomers observed a distinctive four-peaked, accelerating ‘chirp’ in the light from supernova SN 2024afav, interpreted as the birth of a magnetar—an ultra-mense, highly magnetized neutron star—hidden in the exploding star. The signal fits a model where material falling back formed a tilted accretion disk around the magnetar, whose frame-dragging (Lense–Thirring precession) causes the disk to wobble and periodically modulate the supernova’s brightness. From this, the magnetar is inferred to rotate about 4.2 milliseconds and possess a magnetic field about 300 trillion times stronger than Earth's. While this provides strong evidence for magnetars powering some superluminous supernovae, it may not apply to all such events, and future surveys like the Rubin Observatory will seek more examples to map how often magnetars form in stellar explosions.