In first, James Webb Space Telescope spots stars powered by 'dark matter'

Scientists for the past 15 years have been searching for evidence of a type of star only theorised but never observed - one powered not by the fusion of atoms like the sun and other ordinary stars but by enigmatic material known as "dark matter."

"Thanks to the James Webb Space Telescope's (JWST) ability to peer back to the dawn of the universe, the first good candidates to be 'dark stars' have been identified," said a spokesperson.

The three objects spotted by Webb, which was launched in 2021 and began collecting data last year, were initially identified last December as some of the universe's earliest-known galaxies but, according to researchers, instead might actually be "humongous dark stars."

"Dark matter, invisible material whose presence is known mainly based on its gravitational effects at a galactic scale, would be a small but crucial ingredient in dark stars," explained a scientist involved in the research. 

"These stars are described as made almost entirely of hydrogen and helium - the two elements present during the universe's infancy - with 0.1% of their mass in the form of dark matter. But self-annihilating dark matter would be their engine."

"Dark matter is invisible to us - it does not produce or directly interact with light - but is thought to account for about 85% of the universe's matter, with the remaining 15% comprising normal matter like stars, planets, gas, dust and Earthly stuff like pizza and people," the scientist added.

Dark stars would possess a mass at least a million times greater than the sun and a luminosity at least a billion times greater, with a diameter roughly ten times the distance between Earth and the sun.

"They're big puffy beasts," said a theoretical astrophysicist involved in the study. "They are made of atomic matter and powered by the little bit of dark matter that's inside them."

Unlike ordinary stars, dark stars would be capable of gaining mass by accumulating gas falling into them in space.

"They can continue to accrete the surrounding gas almost indefinitely, reaching supermassive status," said a lead author of the study.

Dark stars would not have been as hot as the universe's first generation of ordinary stars since it was the nuclear fusion occurring in the cores of those stars that produced elements heavier than hydrogen and helium.

The three objects identified as potential dark stars date back to early in the universe's history - one from 330 million years after the Big Bang event that initiated the cosmos 13.8 billion years ago, and the others from 370 million years and 400 million years after the Big Bang.

Based on the Webb data, these objects could be either early galaxies or dark stars, according to the researchers.

"One supermassive dark star is as bright as an entire galaxy, so it could be one or the other," they added.

While there is not enough data to definitively determine the nature of these three objects, Webb may be able to gather more comprehensive data on other similarly primordial objects that could provide "smoking gun" evidence of a dark star.

Conditions in the early universe may have been conducive to the formation of dark stars, with high dark matter densities at the locations of star-forming clouds of hydrogen and helium. Such conditions are highly unlikely today.

"It would be really super exciting to find a new type of star with a new kind of heat source," said the theoretical astrophysicist. "It might lead to the first dark matter particles being detected. And then you can learn about the properties of dark matter particles by studying a variety of dark stars of different masses."