A team of astronomers at the University of Hawaii’s Institute for Astronomy has discovered a new type of cosmic explosion, dubbed “extreme nuclear transients” (ENTs). These events occur when massive stars are shredded by supermassive black holes. ENTs are significantly more energetic than normal tidal disruption events and remain luminous for years, surpassing even the brightest supernova explosions.
Researchers led by Jason Hinkle observed a star being ripped apart as a tidal disruption event over several years but found that ENTs are distinct. They reached brightness levels nearly 10 times greater than typical tidal disruption events and remained luminous for extended periods.
One of the studied ENTs, Gaia18cdj, released 25 times more energy than the most powerful supernova on record. It radiated energy equal to the lifetime output of 100 Suns in just one year. The team’s findings suggest that ENTs are millions of times rarer than supernovae but their extreme brightness allows them to be seen across vast cosmic distances.
According to Hinkle, observing ENTs offers a new way to study black holes in the early universe. The team used years of observations from various telescopes to confirm that ENTs are not caused by normal black hole activity or supernovae. Instead, they appear to result from a smooth, drawn-out process where stars multiple times more massive than our Sun are slowly consumed by black holes.
The discovery provides valuable insights into massive black hole growth in distant galaxies. By studying these prolonged flares, researchers can gain insights into the processes that shaped galaxies across cosmic time. Future observatories like the Vera C. Rubin Observatory and NASA’s Roman Space Telescope may uncover many more ENTs, revolutionizing our understanding of black hole activity in the early universe.
“These ENTs don’t just mark the end of a massive star’s life,” said Hinkle. “They illuminate the processes responsible for growing the largest black holes in the universe.”
Source: https://www.hawaii.edu/news/2025/06/04/biggest-explosion-since-big-bang