Scientists at the Center for Astrophysics | Harvard & Smithsonian (CfA) have found that the unique features of supermassive stars align with the similarly unique features of little red dots, a class of objects recently revealed in the distant universe by the James Webb Space Telescope (Webb). This artist’s conception shows a supermassive star roughly one million times the mass of our Sun, loosely bound by an outer envelope and cut away to reveal the structure of its dense core. Akin to their massive counterparts, extremely massive stars feature a convective core where nuclear reactions occur, producing enormous amounts of energy carried to the surface by photons. Despite this, the outer layers are enormously extended and diffused, so that the energy from the core spreads across a huge volume before reaching the surface. This, in turn, lowers the surface temperature of the star, giving it a distinct red appearance. Credit: CfA/Melissa Weiss. High Resolution Image
A new study shows that mysterious “Little Red Dots” seen by NASA’s James Webb Space Telescope are likely supermassive stars, shedding light on the earliest days of our universe
Phoenix, AZ (January 6, 2026)— Using data from NASA's James Webb Space Telescope, astronomers from the Center for Astrophysics | Harvard & Smithsonian (CfA) have revealed the universe's most mysterious distant objects, known as little red dots, may actually be gigantic, short-lived stars.
The findings offer a direct glimpse into how the universe's first supermassive black holes may have formed, marking a breakthrough in scientists' understanding of the early cosmos.
The study was presented today at a press conference during the 247th meeting of the American Astronomical Society in Phoenix, Arizona.
As the universe expands, light from very distant objects stretches to redder colors. Early space-based telescopes like Hubble were built to detect shorter wavelengths of light, and while they saw interesting targets that later turned out to be little red dots, scientists couldn't tell exactly what they were.
In 2022 the first deep images from Webb, a telescope designed to see longer wavelengths of light, revealed little red dots in the distant universe. The new results gave scientists more context into what these mysterious, compact, and very old objects could be.
Past theories explaining little red dots required complicated explanations involving black holes, accretion disks and dust clouds, but the new model shows that a single massive star can also naturally produce all of the key signatures in little red dots: extreme brightness, a distinctive V-shaped spectrum, and the rare combination of one bright hydrogen emission.
Now, for the first time, astronomers have created a detailed physical model of a rare, metal-free, rapidly growing supermassive star about a million times the mass of the Sun, and showed that its unique features are a perfect match for little red dots.
"Little red dots have been a point of contention since their discovery," said Devesh Nandal, an astronomer at the CfA and the lead author of the new study. "But now, with new modeling, we know what's lurking in the center of these massive objects, and it's a single gigantic star in a wispy envelope. And importantly, these findings explain everything that Webb has been seeing."
While stars across a wide range of masses align with both the spectral measurements for little red dots, only the most massive have the right luminosity. Nandal and his colleagues believe that if they can find additional little red dots that are less luminous and massive than those in the study, they will be able to uncover the truth about why and how this happens.
The new results are helping scientists come one step closer to understanding little red dots, providing direct evidence of the final, brilliant moments that occur just before a giant star collapses into a black hole.
"If our interpretation is right, we're not just guessing that heavy black hole seeds must have existed. Instead, we're watching some of them be born in real time," said Nandal. "That gives us a much stronger handle on how the universe's supermassive black holes and galaxies grew."
A new study shows that mysterious “Little Red Dots” seen by NASA’s James Webb Space Telescope are likely supermassive stars, shedding light on the earliest days of our universe
Phoenix, AZ (January 6, 2026)— Using data from NASA's James Webb Space Telescope, astronomers from the Center for Astrophysics | Harvard & Smithsonian (CfA) have revealed the universe's most mysterious distant objects, known as little red dots, may actually be gigantic, short-lived stars.
The findings offer a direct glimpse into how the universe's first supermassive black holes may have formed, marking a breakthrough in scientists' understanding of the early cosmos.
The study was presented today at a press conference during the 247th meeting of the American Astronomical Society in Phoenix, Arizona.
As the universe expands, light from very distant objects stretches to redder colors. Early space-based telescopes like Hubble were built to detect shorter wavelengths of light, and while they saw interesting targets that later turned out to be little red dots, scientists couldn't tell exactly what they were.
In 2022 the first deep images from Webb, a telescope designed to see longer wavelengths of light, revealed little red dots in the distant universe. The new results gave scientists more context into what these mysterious, compact, and very old objects could be.
Past theories explaining little red dots required complicated explanations involving black holes, accretion disks and dust clouds, but the new model shows that a single massive star can also naturally produce all of the key signatures in little red dots: extreme brightness, a distinctive V-shaped spectrum, and the rare combination of one bright hydrogen emission.
Now, for the first time, astronomers have created a detailed physical model of a rare, metal-free, rapidly growing supermassive star about a million times the mass of the Sun, and showed that its unique features are a perfect match for little red dots.
"Little red dots have been a point of contention since their discovery," said Devesh Nandal, an astronomer at the CfA and the lead author of the new study. "But now, with new modeling, we know what's lurking in the center of these massive objects, and it's a single gigantic star in a wispy envelope. And importantly, these findings explain everything that Webb has been seeing."
While stars across a wide range of masses align with both the spectral measurements for little red dots, only the most massive have the right luminosity. Nandal and his colleagues believe that if they can find additional little red dots that are less luminous and massive than those in the study, they will be able to uncover the truth about why and how this happens.
The new results are helping scientists come one step closer to understanding little red dots, providing direct evidence of the final, brilliant moments that occur just before a giant star collapses into a black hole.
"If our interpretation is right, we're not just guessing that heavy black hole seeds must have existed. Instead, we're watching some of them be born in real time," said Nandal. "That gives us a much stronger handle on how the universe's supermassive black holes and galaxies grew."
Resource
Nandal, D et al. Supermassive Stars Match the Spectral Signatures of JWST's Little Red Dots, The Astrophysical Journal, accepted. Draft: https://arxiv.org/pdf/2507.12618
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