Astronomers have spotted a star within the Andromeda galaxy that shone intensely before fading and disappearing from observations. This sequence of events indicates the birth of a black hole, but without the usual cataclysmic phenomenon of a supernova.
Named M31-2014-DS1, this star was tracked using data collected by NASA's NEOWISE mission. Around 2014, its infrared luminosity increased notably, before dropping sharply from 2016 onward. By 2023, it was practically undetectable. A team of astronomers, led by Kishalay De from Columbia University, identified this unusual behavior by sifting through observation archives.
This silent disappearance goes against classical scenarios, according to which massive stars end their existence in a violent explosion. In this specific case, with a mass estimated at 13 times that of the Sun, the star appears to have collapsed directly into a black hole, a process that takes only a few hours. According to the researchers, this observation shows that stars can directly give birth to black holes.
Checks carried out with the Hubble Space Telescope and the James Webb instrument confirmed the absence of the star. The faint infrared glow still detectable comes from a disk of gas and dust rotating around the newly formed black hole. This material, moving too fast to fall directly, forms a swirling structure that gradually feeds the object.
This discovery suggests that a significant number of black holes could form in this discreet way, which would significantly increase their estimated numbers in the cosmos. It also offers a new method for detecting them, by searching for brief infrared flares in nearby galaxies. Scientists can thus identify other stars about to die without undergoing an explosion.
In the future, instruments like the Chandra observatory could capture X-rays once the environment surrounding the black hole clears up. For now, the gas is far too dense to allow this type of radiation to escape. Over time, the infrared signature should continue to diminish, gradually revealing the nature of the object.
By documenting the end of life of a star devoid of explosion, researchers gain essential information about stellar evolution. This particular case in Andromeda opens the door to analyzing other comparable events. The results of this study have been published in the journal
Science, providing a fresh perspective on the physics of stars.