Astronomers have observed a rare cosmic event: the disappearance of a massive star that appears to have collapsed directly into a black hole without a supernova explosion. The star, designated M31-2014-DS1, is located in the Andromeda Galaxy, approximately 2.5 million light-years from Earth, according to NASA.
Typically, stars with significant mass are expected to conclude their lives in a spectacular supernova, a powerful and luminous explosion. Yet, data captured by NASA’s now-retired Near-Earth Object Wide-field Infrared Survey Explorer (NEOWISE) mission revealed an unusual sequence of events for M31-2014-DS1. Instead of exploding, the star gradually dimmed and eventually vanished from view, leaving behind a shell of hot gas and dust.
Archival data indicates that M31-2014-DS1 experienced a brightening in infrared light in 2014. By 2023, however, its visible light output had diminished by a factor of more than 10,000, becoming undetectable. Researchers believe the initial infrared brightening was caused by the shedding of the star’s outer layers as its core ran out of fuel and could no longer withstand the force of gravity.
“This star used to be one of the most luminous stars in the Andromeda Galaxy, and now it was nowhere to be seen,” said Kishalay De, a professor at Columbia University and an associate research scientist at the Simons Foundation’s Flatiron Institute, and a Caltech alumnus. The findings were published Thursday in the journal Science.
Unlike a typical supernova, which is triggered by a powerful shockwave, M31-2014-DS1 appears to have undergone a weaker shockwave, causing most of its material to collapse inward, forming a black hole without the characteristic explosion. This phenomenon provides a recent understanding of how black holes can form quietly, without the dramatic display of a supernova. The research was supported by NASA’s Astrophysics Data Analysis Program.
The NEOWISE mission, managed by NASA’s Jet Propulsion Laboratory (JPL) for NASA, operated from 2009 to 2024, with a two-year hiatus from 2011 to 2013. Data from the mission were processed and archived at IPAC, a data and science center for astronomy at Caltech. Astronomers are now searching for other stars that may follow a similar path to M31-2014-DS1.
The star M31-2014-DS1 had a mass of just 13 times that of our sun, relatively lightweight by typical black hole-forming standards.
