A dark star is a type of star that may have existed early in the universe before conventional stars were able to form and thrive. The stars would be composed mostly of normal matter, like modern stars, but a high concentration of neutralino dark matter present within them would generate heat via annihilation reactions between the dark-matter particles. This heat would prevent such stars from collapsing into the relatively compact and dense sizes of modern stars and therefore prevent nuclear fusion among the 'normal' matter atoms from being initiated.
Under this model, a dark star is predicted to be an enormous cloud of molecular hydrogen and helium ranging between 4 and 2,000 astronomical units in diameter and with a surface temperature and luminosity low enough that the emitted radiation would be invisible to the naked eye.
In the unlikely event that dark stars have endured to the modern era, they could be detectable by their emissions of gamma rays, neutrinos, and antimatter and would be associated with clouds of cold molecular hydrogen gas that normally would not harbor such energetic, extreme, and rare particles.
In April 2023, a study investigated four extremely redshifted objects discovered by the James Webb Space Telescope. Their study suggested that all of them, JADES-GS-z13-0, JADES-GS-z12-0, and JADES-GS-z11-0, are consistent with being point sources, and further suggested that the only point sources which could exist in this time and be bright enough to be observed at these phenomenal distances and redshifts (z = 10-13) were supermassive dark stars in the early universe, powered by dark matter annihilation. Their spectral analysis of the objects suggested that they were between 500,000 and 1 million solar masses (M☉), as well as having a luminosity of billions of Suns (L☉); they would also likely be huge, possibly with radii surpassing 10,000 solar radii (R☉), far exceeding the size of the largest known stars and rivaling that of quasi-stars.
Gamma-rays, particles called neutrinos or antimatter could be tell-tale signs