Mistaken identity: A presumed supernova is actually something much rarer

In a case of comic mistaken identity, an international team of astronomers revealed that what they once thought was a supernova is actually periodic flaring from a galaxy where a supermassive black hole gives off bursts of energy every 114 days as it tears off chunks of an orbiting star.

Source:
https://phys.org/news/2021-01-mistaken-identity-presumed-supernova-rarer.html