No Supernova Needed. This Star Collapsed Directly Into A Black Hole

A team of astronomers led by Kishalay De, a Columbia University astronomy professor, has discovered evidence of a star in the Andromeda Galaxy that collapsed directly into a black hole without exploding as a supernova, a phenomenon predicted by theory but previously lacking observational confirmation, using archival data from NASA's NEOWISE telescope that initially captured the event in 2014, with the findings published in the journal Science in 2026. The star, designated M31-2014-DS1, exhibited unusual behavior over an eight-year period, increasing its mid-infrared flux by 50% between 2014 and 2016 before dramatically fading below detectable levels by 2023. Researchers examined sequential images taken every six months from 2009 to 2022, noting that after its initial brightening phase, the object's optical light faded by a factor of approximately 100 between 2016 and 2019, becoming undetectable in most wavelengths while leaving only a faint near-infrared signature. The discovery provides crucial observational support for the theoretical model explaining how massive stars can bypass the supernova phase. According to the researchers, when a massive star reaches the end of its life, its core collapses and releases neutrinos that drive a shock wave into the star's outer layers. If this shock fails to eject the envelope, it falls back onto the collapsing core, producing a stellar-mass black hole and causing the star to disappear rather than explode. The progenitor star had an initial mass of about 13 solar masses but had shed most of its mass through powerful stellar winds by the time of its collapse, leaving only about 5 solar masses when it formed the black hole. This marks only the second confirmed instance of a direct collapse black hole candidate, with the first being N6946-BH1 observed in 2010 in the NGC 6946 galaxy, which is about 10 times more distant than the Andromeda event. Both objects exhibited similar behavior: an initial increase in luminosity followed by a gradual fading rather than the characteristic explosion of a supernova. '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 explained. The team conducted the largest study ever of variable infrared sources, observing stellar populations across the Milky Way and nearby galaxies but found only one such event, suggesting these direct collapses are rare but significant occurrences in stellar evolution.