Astronomers have witnessed a new kind of supernova caused by a massive star caught in a deadly gravitational dance with a black hole. The event, occurring about 700 million light-years from Earth, provides unprecedented insight into how binary systems can dictate the fate of stars.
The star, at least ten times the mass of our sun, and its black hole companion — of similar mass — were gravitationally bound in a binary system. Over time, the black hole’s immense gravity distorted the star, siphoning off material and stretching it from its spherical shape, ultimately triggering a supernova explosion.
“We caught a massive star locked in a fatal tango with a black hole,” said astrophysicist Alexander Gagliano of MIT’s Institute for AI and Fundamental Interactions, lead author of the study published in the Astrophysical Journal. “After shedding mass for years in a death spiral with the black hole, the star met its finale by exploding. It released more energy in a single second than the sun produces across its entire lifetime.”
The mechanism behind this supernova remains uncertain. Researchers are exploring whether the black hole’s gravitational distortion caused instability that led to the star’s collapse, or if the black hole tore the star apart before it exploded. “The star has been pulled and morphed by the black hole in complex ways,” added co-author Ashley Villar of Harvard University.
This binary system originally consisted of two massive stars orbiting one another. When one star exhausted its life cycle, it exploded in a supernova, leaving behind a black hole. Later, the second star, now in close proximity to the black hole, underwent the newly observed type of supernova.
Detection of the event was enabled by an AI algorithm, designed to spot unusual cosmic explosions in real time. This early warning allowed astronomers to carry out comprehensive observations using multiple ground- and space-based telescopes. Four years of prior data showed bright emissions from the star, likely caused by the black hole consuming its outer hydrogen layer and exposing deeper helium layers.
The aftermath of the supernova revealed further bright emissions as the black hole devoured the remaining stellar debris, growing even more massive and powerful.
“Our takeaway is that the fates of stars are profoundly influenced by their companions,” Gagliano said. “This event gives us an exciting window into how dramatically black holes can impact the deaths of massive stars.”