The Mystery of [tag:dark_matter]Dark Matter[/tag] in [tag:neutron_star]Neutron Stars[/tag] ✛ ✦

Original: "Neutron stars with an agnostic Dark sector: Core and Halo configurations from a two-fluid approach"
arXiv:2607.03840 · 2026-07-04 · CC BY 4.0 · 1 min
Invisible [tag:dark_matter]dark matter[/tag] changes the appearance of [tag:neutron_star]neutron stars[/tag] — perhaps that's how it will be found.

Particles of invisible dark matter can accumulate in a neutron star, the ultra-dense remnant of an exploded star. According to calculations by Einstein, neutron stars can exist, and they are actively studied. Just as in a thick batter, light berries are evenly distributed while heavy nuts sink to the center, so it is with dark matter: its light particles form a cloud around the star, making it fluffy and pliable, while heavier particles gather in the core, squeezing the star into a tight ball.

A star with a dash of light dark matter resembles a fluffy bun that easily gives way when pressed. With heavy particles, it turns into a stale crumb — almost no deformation.

Data from X-ray measurements and recordings of ripples in space from star mergers show that the fraction of dark matter inside a typical neutron star does not exceed 11%. The most unexpected thing: if we ever find two stars of equal mass, but one deforms significantly more under tidal forces, that would be direct proof that dark filling is hidden inside it.

There is five times more dark matter in the Universe than ordinary matter, but no detector has yet caught its particles, and the Standard Model of physics cannot explain them.

If in the TV series 'Dark Matter' it opens doors to other worlds, then in reality, it may be hiding inside dead stars, changing their shape.

\Lambda = \frac{2}{3} k_2 \left(\frac{R}{M}\right)^5
Shows how much a star deforms under tidal forces; depends on the Love number k2 and compactness R/M.
Scientists
Fritz ZwickyVera RubinSubrahmanyan ChandrasekharJocelyn Bell BurnellWolfgang PauliAdam Riess
Concepts
dark star neutron star dark matter nuclear matter metal poor sterile neutrino axion detection neutron stars crust quark core deuteron metallicity in stellar evolution neutrino first stars nucleosynthesis antineutrino equation of state nuclear structure stellar remnant metals galactic halo composition compactness planetary composition formation