Clues to Supernova Mystery Unlocked by ‘Chirp’ Pattern
Astronomers may have solved a cosmic puzzle surrounding a particularly bright supernova, thanks to the observation of a unique pattern in its light curve. The team tracked SN 2024afav, as the event is known, using a network of robotic telescopes from the Las Cumbres Observatory for over 200 days. This allowed them to capture and analyze more than four distinct brightness surges within the supernova’s light curve – a first for this type of stellar explosion.
The analysis revealed that these “bumps” in the light curve progressively weakened, with the intervals between them shortening in a specific way: each interval was approximately 29 percent shorter than the last, according to the research. The team likened this accelerating frequency of brightness surges to the rising pitch of birdsong, leading them to dub the pattern a “chirp.”
Unraveling the Mechanism
Researchers then sought a mechanism to explain this unusual pattern, starting with the magnetar hypothesis. They adjusted the model to reproduce the accelerating sequence of brightness surges. “We tested several ideas, including purely Newtonian effects and also precession due to the magnetar’s magnetic fields,” reported Farah. Precession occurs when the rotational axis of the neutron star is tilted relative to the axis of its magnetic field.
However, that wasn’t enough. It was only when the astronomers incorporated another effect that they were able to reconstruct the observations made of supernova SN 2024afav in their model. “Only the Lense-Thirring precession fit the timing perfectly,” Farah stated. This is a consequence of the General Theory of Relativity, which posits that a rotating mass drags the curved spacetime around with it, causing precession.
Tilted Disks and Dragged Spacetime
Applying this to supernova SN 2024afav means the rotating mass is an accretion disk of ejected stellar material falling back onto the newly formed magnetar. This accretion disk is slightly asymmetrical and tilted relative to the magnetar’s rotational axis. This tilt causes the Lense-Thirring precession to induce a wobble – the disk wobbles like a spinning top.
This wobble explains the periodic brightness surges: “The accretion disk can periodically obscure or reflect the emissions of the magnetar,” the astronomers wrote. This creates the fluctuations. But the shortening intervals can also be explained by the wobbling disk: the magnetar draws material from the disk, shrinking it. It wobbles faster – and generates the observed “chirp” pattern of the brightness surges. This discovery offers latest insights into the complex physics governing these extreme cosmic events.
Mystery Solved?
“Our results thus provide the first observational evidence for the Lense-Thirring effect in a magnetar,” the astronomers wrote. “And they confirm the magnetar model as an explanation for the extreme luminosity of such supernovae.” The team found that their model also fits the light curves of some previously observed superluminous supernovae.
However, whether all stellar explosions of this type are due to magnetars and their wobbling disks remains unclear. The team hopes that upcoming observational data from the Rubin Observatory will provide further insights. The telescope, recently commissioned in Chile, is specifically designed to detect variable phenomena in the sky – including supernovae. (Nature, 2026; doi: 10.1038/s41586-026-10151-0)
Source: Nature, Las Cumbres Observatory
12. March 2026 – Nadja Podbregar
