Astronomers might have witnessed the delivery of a brand-new black gap in our neighboring galaxy, providing one of many clearest glimpses but of how some stars quietly collapse into these cosmic abysses with out the standard fireworks of an explosion.
Whereas scouring archival knowledge from NASA’s NEOWISE mission, a group led by Columbia College astronomer Kishalay De found that one of many brightest stars within the Andromeda Galaxy mysteriously brightened over a decade in the past, pale dramatically after which vanished from view. The star, labeled M31-2014-DS1, lay about 2.5 million light-years from Earth and weighed simply 13 occasions the mass of our solar — comparatively light-weight by typical black hole-forming requirements, in line with De and colleagues’ analysis.
If this detection holds up, he added, “then it actually signifies that there are a lot of extra black holes on the market than what we have anticipated up to now.”
Earlier than it vanished, the star shone roughly 100,000 occasions brighter than our solar. De likened its prominence to Betelgeuse, a well-studied red supergiant that marks the right shoulder of the constellation Orion.
If Betelgeuse were to fade from the sky over a few years, De said, “that would really be shocking and disturbing for us here on Earth, because suddenly Orion wouldn’t look the way it does.”
De and his team first noticed M31-2014-DS1’s strange behavior in data from the NEOWISE mission. Around 2014, the team’s new paper reports, the star brightened in infrared light, then began dimming sharply in 2016, and by 2023 had effectively vanished — fading to roughly one ten-thousandth of its original brightness.
De said he was sitting in front of a computer at the Keck Observatory in Hawaii in 2023, collecting follow-up observations of the star when he noticed something did not add up.
“I remember the moment when we pointed the telescope towards this star — except the star was not there at all,” he recalled. Additional observations from the Hubble Space Telescope and other ground-based observatories confirmed that the star was truly gone. “That’s when it clicked,” De said. “Stars that are this bright, this massive, do not just randomly disappear into darkness.”
According to a leading theory, black holes form when massive stars exhaust their nuclear fuel, triggering an explosive supernova that blasts the star’s outer layers into space that leaves behind either a dense neutron star or a black hole. M31-2014-DS1, however, appears to have formed a black hole without any such fireworks.
“Ten years ago, if someone said a 13 solar-mass star would turn into a black hole, nobody would believe that,” De said. “It was completely outside what was considered the norm.”
De and his colleagues suspect M31-2014-DS1’s small, densely packed core collapsed into a black hole in a matter of hours. What astronomers can still see is not the star itself, but a faint glow in infrared light produced by leftover dust and gas swirling around the newborn black hole.
That material is moving too fast to fall straight in, said De, instead forming a rotating disk that slowly feeds the black hole over time — much like water swirling around a bathtub drain before finally slipping down. Over the next few decades, the infrared signal is expected to fade steadily as more of the remaining debris spirals inward and disappears.
Because the Andromeda Galaxy is relatively close in cosmic terms, the fading debris should remain visible to powerful observatories such as the James Webb Space Telescope (JWST), De said. But directly imaging the black hole itself — as the Event Horizon Telescope has done for much larger black holes — is not possible in this case, at least with current technology, given the object’s small size.
Last year, the team gathered additional data from JWST, whose powerful infrared vision revealed that the black hole remains heavily shrouded in the star’s outer material, according to a preprint posted on arXiv on Jan. 9.
To additional check their conclusion, the researchers additionally used NASA’s Chandra X-ray Observatory to seek for high-energy radiation anticipated from scorching gasoline close to the black gap. No X-rays have been detected, however that was anticipated, De mentioned, as a result of the encircling gasoline is at present too dense to permit the radiation to flee into house.
Over time, as extra materials falls inward and the setting progressively clears, De expects telescopes might ultimately detect X-rays “rising from inside that mess that exists proper now,” doubtlessly revealing the black gap extra immediately.
The findings additionally provide a brand new blueprint for locating related occasions, the researchers say. As a substitute of painstakingly monitoring billions of stars in close by galaxies to see which of them all of the sudden vanish, astronomers can seek for temporary infrared flare-ups — potential warning indicators {that a} star is about to endure a quiet collapse like M31-2014-DS1.
“That is primarily as shut as we are able to get to seeing the demise of a large star,” mentioned De. “Ultimately, I feel it teaches us much more about stellar physics by not exploding.”
A research about this star is reported in a paper revealed Thursday (Feb. 12) in journal Science.
