2023-07-22 06:00:06
The James Webb Space Telescope (JWST) has reportedly found traces of a strange and elusive type of star that only existed at the very beginning of the Universe, when mysterious dark matter was ubiquitous.
Three objects seen by the JWST in December 2022 and identified as galaxies may actually be huge stars powered by dark matter.
Credit: NASA/ESA
According to a recent study by astrophysicist Katherine Freese of the University of Texas at Austin, three of the first objects identified as galaxies by the JWST may actually be dark stars (or dim stars). These entities would be mainly powered by black matter (Matter is the substance that makes up any body having a tangible reality. Its…) rather than by nuclear fusion (Nuclear fusion (sometimes called thermonuclear) is, with fission, one of…).
According to the theory, the dark stars would be huge compared to “ordinary” stars that exist in the Universe today, such as the Sun. They would be composed mainly of hydrogen (Hydrogen is a chemical element with symbol H and atomic number 1.) and helium, with however about one thousandth of their mass consisting of a source of fuel (A fuel is a fuel that powers a heat engine. This transforms …) unusual: dark matter.
Unlike “ordinary” stars, dark stars would have the ability to accrete a lot of matter, making it possible to reach a million times the mass of the Sun and a billion (One billion (1,000,000,000) is the natural number that follows nine hundred…) times its luminosity (Luminosity designates the characteristic of what emits or reflects…).
Map of gas and dark matter in a molten galaxy, with blue and green light (Light is all electromagnetic waves visible to the eye…) indicating a massive core of dark matter at the center of the galaxy (A galaxy is, in cosmology, an assembly of stars, gas, dust and…).
Credit: NASA Goddard
When two dark matter particles collide, they can “annihilate” each other, turning their combined mass into a shower of gamma ray radiation. According to Katherine Freese, this annihilation could occur at any temperature (Temperature is a physical quantity measured using a thermometer and …), which distinguishes dark stars from ordinary stars, which depend on high temperatures for fusion.
The gigantic size of the dark stars would make them appear as extended objects rather than point objects, like current stars. This is how three ancient objects detected by the JWST could have been wrongly identified as galaxies.
However, the dark matter annihilation process cannot continue indefinitely. Dim stars, running out of dark matter fuel, are destined to collapse. They then transform into ordinary stars, fueled by nuclear fusion, or into black holes of several hundred thousand solar masses. Black holes of this mass are actively sought by astrophysicists because it is a missing link to explain the presence of supermassive black holes currently observed. Also, this process would explain that dark stars are no longer observed in the current Universe.
However, confirming the existence of these dark stars through JWST observations would be a major step forward. For Katherine Freese, it would be extremely exciting if the idea of ​​dark stars, which had been pending for many years, was finally proven.
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