The James Webb Space Telescope (JWST) may have detected dark stars, a long-hypothesized object in the early Universe. The finding could help explain why some early galaxies appear too massive too quickly if it is confirmed. Four of the farthest objects yet seen by JWST show signals that researchers believe are consistent with dark stars, and one of them has a distinctive absorption feature at 1,640 Angstrom that points to the presence of ionized helium in its atmosphere.
“Supermassive dark stars are extremely bright, giant, yet puffy clouds made primarily out of hydrogen and helium, which are supported against gravitational collapse by the minute amounts of self-annihilating dark matter inside them,” says Cosmin Ilie, an astrophysicist at Colgate University. “While the signal-to-noise ratio of this feature is relatively low, it is the first time we found a potential smoking gun signature of a dark star. Which, in itself, is remarkable,” Ilie adds.
From a great distance, supermassive dark stars—possibly as massive as a million Suns—may seem like compact galaxies. This research looks at the morphology and absorption spectra of four targets. The study, published in PNAS, connects to work from NASA, ESA, CSA, and STScI theoretical physics more than dark energy discussions.
Examining the initial candidates
The concept of a dark star appears illogical since they are thought to shine through nuclear fusion. Although the light from these hypothetical objects would come from interactions between dark matter particles deep within them rather than from fusion at their cores, they would still be bright. Because self-annihilating dark matter provides the energy support, a dark star in the early Universe can be massive and swollen rather than compact and still be bright enough for the James Webb to detect.
JWST found four extreme objects, three of which are slightly more diffuse and may be dark stars buried beneath surrounding gas, which are regions rich in ionized helium and hydrogen that leave traits in their absorption spectra. It looks like one of the sources is pointed. The strongest clue is the 1,640 Angstrom imprint, which is the line expected from singly ionized helium in a dark star atmosphere. The team notices that this is the first time a candidate has been discovered to possess this trait, despite the weak signal.
Comparing Galaxies and dark Stars
Are these galaxies really just early ones? The researchers acknowledge that this interpretation is still valid for all four objects. However, that path raises a well-known problem: how did such massive systems come together so fast? Dark stars provide a rational alternative. Since they are not powered by nuclear fusion, they do not need to grow at unusual rates in order to stay bloated, bright, and long-lived, matching JWST brightness and shapes.
Eventually, they would collapse into supermassive black holes with massive initial masses, giving a tempting shortcut to the black holes found very early in the universe’s history. Dark stars could then bridge the gap between what we see (very bright early sources) and what we predict (massive black holes forming rapidly), since they are powered by particles rather than unknown astrophysical tricks.
Improving models of the early Universe
Checks for consistency between instruments, sharper absorption spectra, and deeper imaging will all be extremely important. The dark star interpretation would provide the first observational foothold on how dark matter might directly power luminous structures and improve models of the early Universe’s first light sources. If the galaxy interpretation is right, it could help explain how their black holes accumulated mass so rapidly, but it also raises questions about the timelines for the creation of massive systems.
Either way, theoretical physics benefits from the implications.