Up to half of the black holes that devour stars "burp up" their stellar remains years later.
Astronomers made the discovery after spending years watching black holes involved in tidal disruption events (TDEs).
TDEs occur when stars venture too close to black holes. These cosmic monsters' immense gravity exerts incredible tidal forces that stretch and squeeze the stars — a process called spaghettification. The unfortunate stars involved in TDEs are ripped apart or "unraveled" in a matter of hours, signaled by a powerful flash of electromagnetic radiation in visible light.
Some of the stellar material of the destroyed star is flung away from the black hole while the rest forms a thin frisbee-like structure around it called an accretion disk, which gradually feeds that material to the black hole. In its early days, the accretion disk is unstable, and matter sloshes around and smashes into itself, causing outflows detectable by radio waves. But astronomers traditionally only look at these star-eating black holes for a few months following the TDEs.