| Jul 09, 2025 |
Mysterious 'Dark Dwarfs' may be hiding at the heart of the Milky Way
A new kind of cosmic object could help solve one of the universe's greatest mysteries: dark matter.
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(Nanowerk News) Particle Astrophysicists have proposed the existence of a strange new type of star-like object, called a ‘dark dwarf’, which may be quietly glowing in the centre of our galaxy.
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Far from being dark in appearance, these unusual objects are powered by dark matter (the invisible substance thought to make up about a quarter of the universe).
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The discovery comes from a UK-US research team and the full research findings has been published in the Journal of Cosmology and Astroparticle Physics ("Dark dwarfs: dark matter-powered sub-stellar objects awaiting discovery at the galactic center").
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Using theoretical models, the scientists suggest that dark matter can get trapped inside young stars, producing enough energy to stop them from cooling and turning them into stable, long-lasting objects they call dark dwarfs.
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Dark dwarfs are thought to form from brown dwarfs, which are often described as failed stars.
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Brown dwarfs are too small to sustain the nuclear fusion that powers most stars, so they cool and fade over time. But if they sit in a dense pocket of dark matter, like near the Milky Way’s centre, they could capture dark matter particles.
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If those particles then collide and destroy each other, they release energy keeping the dark dwarf glowing indefinitely.
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The existence of these objects depends on dark matter being made of specific kinds of particles, known as WIMPs (Weakly Interacting Massive Particles).
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These are heavy particles that barely interact with ordinary matter, but could annihilate with one another inside stars, providing the energy needed to keep a dark dwarf alive.
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To tell dark dwarfs apart from other faint objects like brown dwarfs, the scientists point to a unique clue: lithium.
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The researchers believe dark dwarfs would still contain a rare form of lithium called lithium-7.
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In normal stars, lithium-7 gets burned up quickly. So, if they find an object that looks like a brown dwarf but still has lithium-7 that’s a strong hint it’s something different.
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Study co-author Dr Djuna Croon of Durham University, said: “The discovery of dark dwarfs in the galactic centre would give us a unique insight into the particle nature of dark matter.”
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The team believes that telescopes like the James Webb Space Telescope could already be capable of spotting dark dwarfs, especially when focusing on the centre of the galaxy.
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Another approach might be to look at many similar objects and statistically determine whether some of them could be dark dwarfs.
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Finding just one of these dark dwarfs, the researchers say, would be a major step towards uncovering the true nature of dark matter.
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