Why do some supernovae flicker in rhythm?

Neutron stars born in binary systems pummel their companion stars with supernova ejecta, causing the companions to swell and shine brighter at predictable intervals. Using detailed models of binary evolution and a new population synthesis code, the team predicted that periodic modulation should appear in over half of hydrogen-poor core-collapse supernovae, with light-curve undulations peaking every 20–50 days and lasting years. They matched observations of three recent supernovae (including SN2022jli) and predict companion stars bright enough to detect with current telescopes, suggesting many hidden periodic signatures wait in archival data.