Plate Nº 76 · recorded November 9, 2026
Space & AstronomyReported finding
Early-Universe Star Collisions Can Build 100,000-Sun Stars
A model finds that dense, early-universe star collisions can create stars above 100,000 Suns, seed black holes and build gas clouds resembling little red dots.
By Elena Vasquez4 min read837 words
In brief
- The densest modeled clusters could assemble stars above 100,000 solar masses.
- Above roughly 100,000 solar masses per cubic parsec, nearly all low-mass systems tested could form stars heavier than 200 Suns.
- The most compact Webb comparison systems could produce very massive stars of 1,000 to 10,000 solar masses.
- With a massive black hole already present, destructive collisions piled up gas at densities matching or exceeding those inferred for LRDs.
- The study appeared in The Astrophysical Journal on October 26, 2026.
By Elena Vasquez
A model of the early universe finds that repeated stellar collisions can build stars exceeding 100,000 times the Sun’s mass, according to a study published October 26, 2026.
Claire E. Williams, a University of California, Los Angeles doctoral student, led the team. The work examines crowded clusters at high redshift, the early-universe era, and tests whether collisions could assemble giant stars, seed black holes and supply gas to the mysterious compact, reddish objects called little red dots, or LRDs.
UCLA astrophysicist Smadar Naoz described the problem this way: “Little red dots are a hot topic in astronomy. You can compare studies of people trying to understand LRDs to the tale of blind people who are trying to describe an elephant by touching it, and each person describes it differently based on what part they’re touching.”
Naoz said the research connects several of those perspectives and may help researchers see more of the “elephant.”
What happens when stars have no black hole?
The authors built a radially resolved analytic model, using equations to track stars at different distances from a cluster’s center. It represents dense systems resembling the ancestors of globular clusters, nuclear star clusters such as the one around the Milky Way’s central black hole, and compact LRDs.
They drew starting conditions from high-resolution cosmological simulations rather than observations. The team then checked its predictions against Monte Carlo computer simulations, which use repeated randomized trials, and found good agreement across key regimes.
Without a black hole, collisions tended to be gentle mergers rather than destructive smash-ups. The merged stars then sank toward the center through dynamical friction, a drag-like orbital process, where repeated collisions could assemble a very massive star.
- At densities above roughly 100,000 solar masses per cubic parsec, a unit of astronomical volume, nearly all the low-mass systems tested could form a very massive star heavier than 200 Suns.
- In the densest cases, the assembled star grew beyond 100,000 solar masses. The model says it could collapse into an intermediate-mass or even supermassive black hole.
“Perhaps the strangest outcome of our simulations is that stars can merge repeatedly within the cluster until they form one gigantic star with a mass equal to that of an entire cluster,” Williams said. She noted that models suggest such a star may have no option at the end of its life but to collapse into itself and form a massive black hole.
Takeaway: Without a black hole, collisions can pile stars into one another, creating a central heavyweight that may become a black hole.
How does the model compare with Webb observations?
The team compared its model with lensed star clusters observed at high redshift by the NASA/ESA/CSA James Webb Space Telescope. Lensing uses foreground gravity to magnify an image. Most of those systems form only modest very massive stars, but the most compact could reach 1,000 to 10,000 solar masses.
The nearby Galactic Center offers another comparison because stellar collisions are common there. In the model, a very massive star that turns into an intermediate-mass black hole leaves a system resembling the Galactic Center: a black hole surrounded by a dense star cluster.
Takeaway: The comparison ranges from modest collision-built stars to 10,000-Sun objects in the most compact systems.
What changes when a black hole is already there?
With a massive black hole already in the cluster, the result changes. Its gravity speeds stars in the inner region, making collisions destructive. Instead of merging gently, the stars tear each other apart and spill their material into the surrounding space.
The process rapidly piles up extremely dense gas around the black hole. The model reaches densities that match or exceed those inferred for LRDs.
The researchers concluded that high rates of destructive collisions can rapidly build extremely dense gaseous environments around massive black holes, potentially providing an analog to the observed population of LRDs. That gas could serve as ready fuel and might help explain why the objects look as they do.
Takeaway: A pre-existing black hole can turn stellar mergers into destructive events that concentrate the dense gas associated with LRDs.
How firm are the conclusions?
The findings remain model-based rather than a report of a directly observed 100,000-Sun star. The authors drew starting conditions from cosmological simulations, checked their equations against Monte Carlo methods and found agreement in key regimes. The LRD connection stays conditional: the model says the gas could be fuel and might help explain their appearance.
The paper appeared in The Astrophysical Journal as Claire E. Williams et al. (2026), A Cosmological Framework for Stellar Collisions at High Redshift in Proto-globular Clusters, Nuclear Star Clusters, and Little Red Dots, ApJ 1012, 1; DOI: 10.3847/1538-4357/aea577.
Takeaway: The study offers a plausible route from early cluster collisions to giant stars, black holes and LRD gas, not a confirmed account of any one object.
via sci.news (Source)
More from Elena Vasquez
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Correspondent covering money, funding and market shifts around general science news at SciBeat.
384 articles
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