A team of astronomers recorded the entire process in which a massive star disappears from sight to transform directly into a black hole. The phenomenon occurred in the galaxy of Andromeda and defies common scientific expectation, since the star did not end its life with the usual explosion of supernova.
The star, identified as M31-2014-DS1is located about 2.5 million light years from Earth. The group of experts, under the leadership of Kishalay Deresearcher of Flatiron Institute of the Simons Foundationanalyzed data collected between 2005 and 2023 by various space and ground telescopes.
This finding offers the most complete observational record to date on the birth of a black hole of stellar origin. According to the results published by the magazine Sciencethe core of the star collapsed suddenly, while its outer layers were slowly and turbulently ejected.
“This is just the beginning of the story,” he said. Kishalay De on the relevance of the discovery. The lead author of the study noted that light from the dust debris surrounding the new black hole will be visible for decades to highly sensitive instruments such as the James Webb Telescope.
This is because «it will continue to fade very slowly,» according to Kishalay De en a statement. «And this could end up being a reference for understand how black holes form stars in the universe,» he added.
The historical record of the star reveals that its infrared brightness increased in 2014 and then dimmed drastically in 2016. By 2022 and 2023, the star was already practically invisible in the optical spectrum, with a luminosity that represents barely one ten-thousandth of its original brightness.
Kishalay De compared the magnitude of the event to a hypothetical scenario in our own galaxy. “Imagine if the star Betelgeuse suddenly disappeared. Everyone would lose their minds! The same thing happened with this star in Andromeda,” said the scientist.
From massive star to black hole without supernova
The physical process behind this disappearance is due to the breakdown of the balance between gravity and the internal pressure of the star. When a star with a mass ten times greater than that of the Sun runs out of fuel, gravity triumphs, and the core compresses into a dense neutron star.
In most cases, the emission of neutrinos generates a shock wave that tears the star apart in a supernova. However, if this wave fails in its attempt to expel the material, the theory suggests that the matter falls back onto the center and creates a black holejust as happened in this extraordinary event.
The research highlights that convection, a process derived from temperature differences within the star, prevented all the matter from falling suddenly into the void. Andrea Antonico-author of the study, explained that this phenomenon causes the material to orbit the black hole instead of being absorbed immediately.
Antoni maintained that, due to the momentum of this material, the decline process takes decades instead of months. The researcher specified that the gas describes a trajectory similar to that of water that rotates around a drain before disappearing completely.
This discovery allowed scientists to reinterpret observations of other similar objects, such as the star NGC 6946-BH1. According to Kishalay De, these findings are fundamental pieces to putting together the puzzle of which stars become black holes and how they do so.
Behind the research are scientists from the Simons Foundation – from the Massachusetts Institute of Technology – and from the American universities of Harvard, Princeton and Columbia, among others.
