Astronomers Witness Star’s Quiet Collapse into Black Hole in Andromeda Galaxy
In a rare discovery, astronomers have observed a star in the Andromeda Galaxy seemingly disappear, indicating a direct collapse into a black hole without the typical supernova explosion. The findings, published in the journal Science on February 12, 2026, offer a unique glimpse into the formation of black holes and challenge existing assumptions about stellar death.
A Star Vanishes in Andromeda
The star, designated M31-2014-DS1, was a dying supergiant located 2.5 million light-years away in the Andromeda Galaxy. Researchers analyzing archival data from NASA’s Near-Earth Object Wide-Field Infrared Survey Explorer (NEOWISE) mission noticed the star’s unusual behavior. Initially, M31-2014-DS1 increased in brightness in the infrared spectrum starting in 2014, peaking over two years and then rapidly faded over the following year, eventually becoming undetectable in optical light by 2023.
“This has probably been the most surprising discovery of my life,” said Kishalay De, lead author of the study and a professor at Columbia University, in a press release. “The evidence of the disappearance of the star was lying in public archival data and nobody noticed for years until we picked it out.”
How NEOWISE Revealed the Collapse
The NEOWISE mission, which operated from 2009 to 2024, was designed to detect near-Earth objects but also collected a wealth of data on stars and other celestial objects. Researchers, including De, were sifting through this data looking for variable sources when they identified M31-2014-DS1. The team examined images taken every six months between 2009, and 2022.
Follow-up observations with the Hubble Space Telescope in 2022 revealed nothing in optical light, with only a faint source detected in the near-infrared. Subsequent observations with the Keck Observatory in 2023 confirmed the faint near-infrared source.
Direct Collapse vs. Supernova
Traditionally, massive stars are thought to end their lives in a spectacular supernova explosion, leaving behind either a neutron star or a black hole. However, theoretical models have suggested that some massive stars might undergo a “direct collapse” into a black hole without a supernova. This happens when the star’s core collapses under gravity, and the resulting shock wave fails to eject the outer layers of the star.
“Stars with this mass have long been assumed to always explode as supernovae,” De explained. “The fact that it didn’t suggests that stars with the same mass may or may not successfully explode, possibly due to how gravity, gas pressure, and powerful shock waves interact in chaotic ways with each other inside the dying star.”
A Second Candidate: N6946-BH1
This isn’t the first hint of a direct collapse black hole. In 2010, astronomers identified another candidate, N6946-BH1, in the galaxy NGC 6946, located about 25 million light-years away. Like M31-2014-DS1, N6946-BH1 also brightened and then faded without a visible supernova. However, due to its greater distance, the data for N6946-BH1 is less detailed than that available for the Andromeda star.
Future Observations and the Vera Rubin Observatory
The discovery highlights the difficulty in identifying these quiet black hole formations. Supernovae are easily detectable due to their intense brightness, while direct-collapse events are far more subtle.
“Unlike finding supernovae which is easy because the supernova outshines its entire galaxy for a few weeks, finding individual stars that disappear without producing an explosion is remarkably difficult,” De said.
The upcoming Vera Rubin Observatory, with its Legacy Survey of Space and Time, is expected to significantly increase the detection rate of these events, providing a larger sample size for study and furthering our understanding of stellar death and black hole formation.