For the first time, astronomers have fully observed a massive star’s failure to explode as a supernova, instead collapsing directly into a black hole. This rare event offers the clearest picture yet of how a massive star transforms into a black hole—a cosmic process previously understood largely through theory.
The research, published in the journal Science, combines over a decade of archival data with recent observations from various ground and space-based telescopes. These findings mark a new chapter in understanding the origins of black holes, a phenomenon that continues to fascinate scientists and the public alike.
A Giant Star’s Sudden Disappearance
The star at the center of this discovery, designated M31-2014-DS1, is located approximately 2.5 million light-years from Earth in the Andromeda Galaxy—our closest galactic neighbor. Understanding stellar evolution in nearby galaxies provides valuable insights into the processes occurring throughout the universe.
From 2005 to 2023, researchers analyzed data from NASA’s NEOWISE project and other telescopes, identifying an unusual pattern:
- In 2014, the star’s infrared light began to increase.
- By 2016, the star had dramatically dimmed within less than a year.
- Between 2022 and 2023, the star practically disappeared in visible and near-infrared light—its brightness reduced to one ten-thousandth of its original level.
Currently, only a faint signal remains, detectable in mid-infrared light, with a brightness about one-tenth of its initial state.
“This star was once among the brightest in Andromeda, and then suddenly it wasn’t there anymore,” said Kishalay De, the lead researcher of the study from the Flatiron Institute. He likened the event to what would happen if the star Betelgeuse in our own sky were to suddenly vanish, causing widespread excitement in the astronomical community.
Based on these dramatic changes in light, the researchers concluded that the star’s core had collapsed and transformed into a black hole.
Why Didn’t It Explode as a Supernova?
Stars typically generate energy by fusing hydrogen into helium in their cores. This process creates outward pressure that balances the inward pull of gravity.
However, when a star with a mass 10 times or greater than our Sun runs out of fuel, this balance collapses. Gravity takes over, and the core collapses to form an incredibly dense neutron star.
In many cases, the release of particles called neutrinos triggers a powerful shockwave that blasts away the star’s outer layers in a spectacular supernova explosion. However, in certain instances—such as with M31-2014-DS1—that shockwave fails to expel the material.
most of the star’s material falls back into the center, forming a black hole.
“We’ve known about the existence of black holes for almost 50 years,” De stated. “But we are still in the early stages of understanding which stars turn into black holes and how that process happens.”
The Hidden Role of Convection
A key finding of this study is the role of convection—the movement of gas caused by extreme temperature differences within the star.
The star’s core is incredibly hot, while its outer layers are much cooler. This difference creates turbulent, up-and-down gas movement.
As the core collapses, the outer layers are still moving rapidly due to this convection. Theoretical models suggest that this movement prevents all the material from immediately falling into the black hole. Instead, the inner layers form an orbit around the black hole, the outer layers are slowly pushed outward, and the ejected material cools and forms cosmic dust.
