Do the legendary “dark stars” really exist? James Webb seems to have detected 3 strange candidates for stars fueled by dark matter.
For the past 15 years, scientists have been searching for evidence of a type of star that has only been hypothesized but never observed: one that doesn’t feed on the fusion of atoms like the Sun and other ordinary stars, but from a mysterious matter called dark matter.
Thanks to the ability of the James Webb Space Telescope (JWST) to go back to the dawn of the universe, the first good candidates for “dark stars” have been identified.
“They’re big bloated beasts,” says Katherine Freese, a theoretical astrophysicist at the University of Texas at Austin and lead author of the research published in the Proceedings of the National Academy of Sciences.
“They are made of atomic matter and powered by the little bit of dark matter that is inside them,” Freese added.
Primitive galaxies or dark stars?
The three objects identified as possible dark stars date from the earliest years of the Universe’s history: one from 330 million years after the Big Bang that launched the cosmos 13.8 billion years ago, and the others from 370 and 400 million years ago. years after the Big Bang.
Based on the Webb data, these objects could be primitive galaxies or dark stars, Freese explains.
According to Freese, although there is not enough data available to make a definitive judgment on these three objects, Webb may be able to obtain more complete data on other similar primordial objects that could provide strong evidence for the existence of a dark star.
In that sense, according to a press release from the University of Texas at Austin, James Webb’s follow-up observations of the spectroscopic properties of objects—including dips or excesses of light intensity in certain frequency bands—could help. to confirm whether these candidate objects are really dark stars.
“Tune something within the standard model”
Confirming the existence of dark stars could also help solve a problem created by James Webb: there seem to be too many large galaxies too early in the universe to fit the predictions of the Standard Model of cosmology.
“It’s more likely that something within the standard model will have to be fine-tuned, because coming up with something totally new, like we did, is always less likely,” Freese says. “But if some of these objects that look like primitive galaxies are actually dark stars, the simulations of galaxy formation agree better with the observations.”
James Webb: possible huge dark stars
The three objects detected by Webb, which launched in 2021 and began collecting data last year, were initially identified last December as some of the earliest known galaxies in the universe, but the researchers say they could actually be huge dark stars. .
Dark matter, invisible material whose presence is known primarily through its galactic-scale gravitational effects, would be a small but crucial ingredient in dark stars. These stars have been described as being made up almost entirely of hydrogen and helium – the two elements present during the infancy of the universe – with 0.1% of their mass in the form of dark matter. But the dark matter that self-annihilates would be its engine.
Dark matter, 85% of the universe
Dark matter is invisible to us – it does not produce light or directly interact with it – but it is believed to represent about 85% of the matter in the universe, while the remaining 15% is made up of normal matter such as stars, planets, gas and dust.
Dark stars could reach a mass at least a million times that of the Sun and a luminosity at least a billion times that of the Sun, with a diameter roughly ten times the distance between Earth and the Sun.
Unlike ordinary stars, they would be able to gain mass by accumulating the gas that falls on them in space.
“They can continue to accumulate the gas around them almost indefinitely, until they reach the state of supermassive,” explains Cosmin Ilie, an astrophysicist at Colgate University and author
source: https://arxiv.org/abs/2304.01173