The James Webb Space Telescope has been picking up little red dots in almost every image,
writes Quanta magazine. And now two teams of astronomers propose they're looking at a new astronomical object: a black hole star. It shines with the light of billions of suns — and hides a black hole in its core.
But Quanta adds that "not everyone agrees with this bold interpretation."
[Two Webb telescope surveys of distant objects included little red dots] for hours at a time. They tabulated precisely what shades of light were coming from each dot, and how bright the shades were... The bombshell discovery in the little red dot spectra was that the colors of hydrogen were smeared out across multiple shades. Usually, seeing such an effect means you're looking straight at an exposed black hole. Black holes whip hydrogen clouds around them at furious rates, with the clouds emitting slightly different colors depending on their speed...
Then, in the spring of 2025, [two of the paper's astronomers] de Graaff and Naidu's teams unveiled the two strangest dots yet... The new little red dots couldn't literally be stars — they were way too bright. And they didn't look much like black holes either. Black holes have an assortment of ringlike structures of different temperatures... Naidu and de Graaff concluded that they were[ looking at the first examples of something combining the vigor of a black hole with the outward appearance of a star: a black hole star... This black hole would pull gas around it, dramatically heating it and pushing light and energy outward, which would keep the outer layers of hydrogen from collapsing inward. In this way, the black hole would form the "engine" of the star, analogous to the fusion-powered core of our sun... "We are seeing the seed," Naidu said. "This is the birth of potentially every massive black hole in the universe."
"Astronomers have spent the last year in a lively debate about what's really going on," Quanta adds. And this week simulations using the Japanese Supercomputer ATERUI III "have explained the nature of the Little Red Dots without requiring any exotic assumptions," writes Phys.org — by conducting the most detailed cosmological simulations yet of conditions in the early universe:
The simulations show that the Little Red Dots are black holes growing at a rate that would be impossible today because of conditions in the early universe. The simulations show that in the early universe, intense far-ultraviolet (FUV) radiation from nearby galaxies suppresses star formation in gas clouds, so rather than forming many small stars, the gas can form a single supermassive star, which then collapses into a black hole seed.
The simulations show that, once formed, these black hole seeds are surrounded by dense gas disks. This environment traps radiation, enabling the black holes to grow at rates dozens of times faster than would be possible in the modern universe. The simulated properties of these rapidly growing black holes provide a good match to the Little Red Dots (LRDs) observed by the James Webb Space Telescope (JWST).
writes Quanta magazine. And now two teams of astronomers propose they're looking at a new astronomical object: a black hole star. It shines with the light of billions of suns — and hides a black hole in its core.
But Quanta adds that "not everyone agrees with this bold interpretation."
[Two Webb telescope surveys of distant objects included little red dots] for hours at a time. They tabulated precisely what shades of light were coming from each dot, and how bright the shades were... The bombshell discovery in the little red dot spectra was that the colors of hydrogen were smeared out across multiple shades. Usually, seeing such an effect means you're looking straight at an exposed black hole. Black holes whip hydrogen clouds around them at furious rates, with the clouds emitting slightly different colors depending on their speed...
Then, in the spring of 2025, [two of the paper's astronomers] de Graaff and Naidu's teams unveiled the two strangest dots yet... The new little red dots couldn't literally be stars — they were way too bright. And they didn't look much like black holes either. Black holes have an assortment of ringlike structures of different temperatures... Naidu and de Graaff concluded that they were[ looking at the first examples of something combining the vigor of a black hole with the outward appearance of a star: a black hole star... This black hole would pull gas around it, dramatically heating it and pushing light and energy outward, which would keep the outer layers of hydrogen from collapsing inward. In this way, the black hole would form the "engine" of the star, analogous to the fusion-powered core of our sun... "We are seeing the seed," Naidu said. "This is the birth of potentially every massive black hole in the universe."
"Astronomers have spent the last year in a lively debate about what's really going on," Quanta adds. And this week simulations using the Japanese Supercomputer ATERUI III "have explained the nature of the Little Red Dots without requiring any exotic assumptions," writes Phys.org — by conducting the most detailed cosmological simulations yet of conditions in the early universe:
The simulations show that the Little Red Dots are black holes growing at a rate that would be impossible today because of conditions in the early universe. The simulations show that in the early universe, intense far-ultraviolet (FUV) radiation from nearby galaxies suppresses star formation in gas clouds, so rather than forming many small stars, the gas can form a single supermassive star, which then collapses into a black hole seed.
The simulations show that, once formed, these black hole seeds are surrounded by dense gas disks. This environment traps radiation, enabling the black holes to grow at rates dozens of times faster than would be possible in the modern universe. The simulated properties of these rapidly growing black holes provide a good match to the Little Red Dots (LRDs) observed by the James Webb Space Telescope (JWST).
Read more of this story at Slashdot.