Many astronomers concluded that supermassive black holes peppered the early universe, absorbing the light of stars in their host galaxies. If the little red dots were black holes, their reddish appearance could be explained by dust — granular material far more complex than gas — obscuring their blue light.
Yet they remained puzzling. Most supermassive black holes exhibit flickering as they consume irregular streams of surrounding gas, and they emit powerful X-rays across the cosmos. The majority of little red dots appeared to display neither behavior.
However, this did not greatly concern astronomers, who expected some strangeness amid the chaos of the early universe. Moreover, black holes were not violating any established cosmological principles.
Then, in the spring of 2025, the teams led by de Graaff and Naidu revealed the two most peculiar little red dots yet.
A New Interpretation
What set these two little red dots apart was the extremity of their redness. Webb detected almost no light in the bluer portions of their spectra, and at a specific shade of red, the brightness surged dramatically. This feature, known as a Balmer break, is characteristic of a hot ball of hydrogen gas — typically found in certain types of stars or galaxies composed of many stars. Deep within a star’s core, nuclear fusion generates heat and light that gradually rises to the surface. There, hydrogen atoms can become energized in a way that blocks bluer wavelengths while allowing redder ones through. These red colors exhibit a hump-shaped spectrum that reveals the overall temperature of the star’s surface.
But the new little red dots could not literally be stars — they were far too luminous. Nor did they closely resemble black holes. Black holes display a variety of ringlike structures at different temperatures and typically do not produce a Balmer break or the smooth red, hump-shaped curve indicative of a stellar surface burning at roughly 5,000 Kelvin.
Rohan Naidu, an astronomer at the University of Hawai’i, co-led a survey team that discovered the reddest little red dot yet. He suggests it’s a member of a whole new class of astrophysical object.
Naidu and de Graaff concluded that they were observing the first examples of an object combining the energy of a black hole with the outward appearance of a star: a black hole star.
From the outside, a black hole star would resemble a vast agglomeration of hydrogen gas. If our sun were replaced by one, it would extend a dozen times farther than Pluto’s orbit. Toward the outer edge, the star would boil unstably, shedding outer layers and explosively ejecting mass. “It’s going to be a very messy system where stuff is being blown out and falling back in,” de Graaff said. “I wouldn’t want to come too close.”
Deep at the center, hidden from the outside world, the star would be powered by a black hole. This black hole would draw in surrounding gas, heating it dramatically and pushing light and energy outward, preventing the outer hydrogen layers from collapsing inward. In this way, the black hole would serve as the star’s “engine,” analogous to the fusion-powered core of our sun. Moving outward, material spiraling around the black hole would emit a range of colors that would gradually make their way toward the surface. As with certain stars, hydrogen near the surface would block bluer light while allowing redder light to pass through. The result would be a gaseous surface shining as brightly as a more exposed black hole but displaying the Balmer break and smooth red hump characteristic of a 5,000-kelvin star, de Graaff and Naidu theorized. As an added benefit, the gas “cocoon” would also absorb X-rays and suppress flickering — which would explain two mysteries surrounding other little red dots.
But what about the broad spectral lines, supposedly caused by hydrogen swirling rapidly around a black hole? Another group offered a possible explanation.
In all the millions of [observations] we’ve taken with ground-based telescopes, there’s nothing that looks like these sources.
Anna de Graaff, Max Planck Institute for Astronomy
The team, which included Vadim Rusakov, an astronomer at the University of Manchester, had been scrutinizing the broad lines of the best-observed little red dots. Broad lines take the shape of a sharp peak. But Rusakov and collaborators noticed that in many cases, these peaks sloped slightly more gently than expected if they originated from fast-moving gas around a black hole. They proposed that instead of arising from rotating gas, much of the spread in hydrogen colors could result from light scattering off electrons.
They computationally removed the effect of this electron-induced smearing from their data, Rusakov said. After doing so, the broad lines no longer appeared quite so broad and instead resembled light passing through a slowly churning shell of hydrogen gas in a particular state — similar to what one would expect from a black hole star. The three teams — de Graaff’s, Naidu’s, and Rusakov’s — published their findings on March 20, 2025 — dubbed “black hole star date” by some of the researchers.
Black hole stars could represent a new developmental stage for supermassive black holes: first, a black hole forms in the center of a hydrogen shell alongside a baby galaxy of ordinary stars. Then, over time, the black hole eats its way out of its cocoon, growing in mass as it clears away the hydrogen gas.
“We are seeing the seed,” Naidu said. “This is the birth of potentially every massive black hole in the universe.”
The Argument Against
Proponents of the black hole star theory invoke Occam’s razor, arguing that their model provides the simplest explanation for these two little red dots — and perhaps for little red dots in general. But simplicity is subjective, and astronomers have spent the past year engaged in spirited debate over what is truly going on.
Even years after the first little red dot was discovered, much about them remains unresolved. Dale Kocevski, an astrophysicist at Colby College, recalls leading a discussion about them at an April 2026 conference in Aspen, Colorado. He began by recapping what he had hoped would be an uncontroversial observation about their trace amounts of blue light. “The group erupted into argument, and we couldn’t even get past the first bullet point,” he said.
Many astronomers continue to maintain that little red dots are traditional black holes — including the newest pair. “The data is really compelling,” said Roberto Maiolino of the University of Cambridge. “I’m a little bit more dubious about the interpretation.”
For each point in favor of black hole stars, Maiolino offers a swift rebuttal. The lack of flicker? In the early universe, black holes may have had a steadier supply of matter and therefore ate more calmly. The absence of X-rays? Standard galactic black holes are encircled by a thick doughnut of gas and dust that can block most X-rays. He sees no reason to suspect the little red dots of being anything other than standard supermassive black holes.
Roberto Maiolino, an astronomer at the University of Cambridge, argues that standard textbook models of black holes — no star required — can explain both old and new observations. Courtesy of Roberto Maiolino
The extreme redness of the new objects is striking, he said, and he agrees it indicates a substantial quantity of gas between the black hole and our line of sight. But that gas could take the form of the doughnut structure, or of puffy clouds filling patches of the black hole’s sky, rather than the uniform shell of gas surrounding a black hole star. Maiolino agrees that electron scattering likely contributes to broadening the spectral lines of some little red dots. However, he notes that electron scattering also smears hydrogen lines from supermassive black holes.
Maiolino and his collaborator, Piero Madau of the University of California, Santa Cruz, argue that the redness of the dots arises primarily from the angle at which we observe them. The reddest dots are those we happen to view edge-on, their gassy doughnuts obstructing our sight. Webb also reveals some “little blue dots,” which could be the same exposed black holes viewed from above, Maiolino and Madau pointed out in spring 2026. They too appeal to Occam’s razor — in this case arguing that black holes offer the simpler explanation for dots of every color.
At this stage, either theory — black hole or black hole star — could account for what Webb has observed. “I don’t think that there is a compelling reason to prefer one or the other,” said Mauro Giavalisco, an astronomer at the University of Massachusetts, Amherst, who has spent much of his career interpreting the spectra of distant galaxies.
To test their respective interpretations, astronomers need a clearer picture of how black hole stars might form and what they would precisely look like.
Return of the Quasi-Star
Over the past few years, Mitchell Begelman has been teaching a graduate seminar on little red dots at the University of Colorado, Boulder. It has kept him immersed in the flood of papers emerging on the subject. Among these mysterious objects — neither quite stars nor quite black holes — he recognized a figure from his past: the quasi-star. “Suddenly the switch flipped, and I realized this is what quasi-stars should look like,” Begelman said.
The field has gotten very polarized.
Anna-Christina Eilers, Massachusetts Institute of Technology
Begelman originally proposed the existence of quasi-stars in 2006, alongside Marta Volonteri and Martin Rees, to explain observations that appeared to show impossibly massive black holes.
The quasi-star theory presents one pathway to forming a black hole star: the core of a vast gas cloud collapses to directly produce a black hole, with the remainder of the cloud accumulating around it.
In 2025, Begelman and his collaborator Jason Dexter applied the quasi-star model to little red dots. They estimated that quasi-stars could assemble themselves within a few million years before settling into a more mature form that would closely resemble little red dots. This process could persist for tens of millions of years — long enough for Webb to detect them.
In 2026, Giavalisco worked with a team to develop the quasi-star model as an origin story for black hole stars, which he considers a natural way to explain how little red dots could conceal the signatures of a feeding black hole. He points out that our sun performs a similar trick, hiding its explosive fusion — just on a far smaller scale. “We have billions and billions of hydrogen bombs exploding every second, and yet we see none of them,” he said.
Giavalisco and his collaborators found that their updated quasi-star model fit the spectra of de Graaff’s and Naidu’s objects even better than the initial models had. He considers the quasi-star theory a plausible explanation for little red dots while remaining open to other possibilities. “I just want to know the truth,” he said.
In the meantime, researchers are beginning to search for another distinguishing pattern: if little red dots are black hole stars formed in the early universe, they should grow increasingly rare over time as each one breaks free from its shell and exposes its inner black hole.
In an August 2026 census of both red and blue dots, categorized across different cosmic eras, Kocevski of Colby College and his collaborators found exactly that pattern. In the data, as the universe aged to between 2 and 3 billion years, little red dots appeared to fade away — preliminary evidence that little red dots, as black hole stars, may genuinely represent a puberty-like phase in the evolution of many supermassive black holes.
Theorists are already working out what that puberty-like phase might entail. In a separate analysis posted on September 8, Naidu, de Graaff, Eilers, and their colleagues tested various techniques for determining the mass of the black hole “seed” hidden within a black hole star. These concealed black holes appeared to be far less massive than standard, exposed black holes. The scientists propose that Webb is catching supermassive black hole stars — up to a million times the mass of the sun — in the act of incubating the universe’s first enormous black holes.
Some researchers, including Kocevski, remain uncertain. Kocevski suspects that the universe is a messy place, and that some little red dots are genuinely as starlike as the black hole star camp maintains, while others will be more akin to standard black holes, as the opposing camp argues. “I have a sneaking suspicion that we’re both right,” he said.
