Astrophysicists at the University of Melbourne in Australia were able to determine the rate at which dark matter is captured by the interior of a neutron star.
The authors of the new work studied ways to search for dark matter: it is difficult to detect it, since it hardly interacts with ordinary baryonic matter.
The researchers drew attention to the fact that neutron stars can help in the search: they, due to their density, can catch dark matter particles that pass through them. The mass of neutron stars is comparable to that of the sun, but the radius is several times smaller – up to ten kilometers.
Scientists said that in theory, dark matter particles collide with neutrons in a star, because of this, they lose energy and find themselves in a gravitational trap. As a result, dark matter collects in the core of the star. This process, according to the authors, will lead to an increase in the temperature of old, cold neutron stars. This can be seen when viewed from Earth.
In extreme cases, this can cause a neutron star to suddenly collapse into a black hole.
To identify and locate abnormally heated neutron stars, you need to know the exact rate of capture of dark matter. Until now, estimates of the capture rate from the Sun have been used for this. But neutron stars differ from ordinary stars in their extremely extreme environment, which greatly affects the scattering of dark matter particles.
The authors note that they studied the structure of neutrons and the interactions between them. This does not fit into the framework of the traditional model, where neutrons are considered as point particles that form an ideal gas.
As a result, it was found that these factors reduce the transfer of energy when dark matter particles collide with neutrons, and also suppress the capture rate. This suppression of capture is enhanced to three orders of magnitude in very massive neutron stars.