Compact stars due to their enormous gravitational field can accumulate a sizable amount of dark matter in their interior. Depending on its nature, accumulated dark matter may affect the properties of neutron stars in quite different ways. I will give an overview of the impact of dark matter on various observable properties of neutron stars with the main emphasis on their thermal evolution. Particularly, I will show the effect of asymmetric fermionic dark matter on the thermal evolution of neutron stars. No interaction between dark matter and baryonic matter is assumed, except the gravitational one. Using the two-fluid formalism, I will demonstrate that dark matter accumulated in the core of a star pulls inwards the outer baryonic layers of the star, increasing the baryonic density in the neutron star core. As a result, it significantly affects the star's thermal evolution by triggering an early onset of the nucleonic and hyperonic direct Urca processes. The second effect is related to the modification of the photon emission from the surface caused by the decrease of the radius. I will discuss the importance of neutron star observations at various distances from the Galactic center. Given that the dark matter distribution peaks toward the Galactic center, neutron stars within this central region are expected to harbor higher fractions of dark matter, potentially leading to distinct cooling behaviors.
Organized by: Catarina Cosme