Capturing and destroying dark matter could heat up isolated, old neutron stars.

A team of particle physicists from the University of Melbourne, Australian National University, King’s College London, and Fermi National Accelerator Laboratory has discovered that the energy transferred when dark matter particles collide and disappear in a cold neutron star can cause the star to rapidly It was calculated that it would be heated to Previously, this warming was thought to be irrelevant because this energy transfer takes a very long time, in some cases longer than the age of the universe itself.

A number of recent studies have focused on capturing dark matter in neutron stars as sensitive probes of the interaction of dark matter with ordinary matter. This could potentially be used to test interactions between dark matter in a way that greatly complements experiments on Earth, especially since dark matter is accelerated to relativistic speeds when it falls into a neutron star. there is. In some cases, neutron star technology could be used to study interactions that are difficult or impossible to observe with experiments that directly detect dark matter. These include dark matter that is too bright to leave a detectable signal in nuclear recoil experiments, and interactions where non-relativistic scattering cross sections are momentum suppressed. Recently, it has been suggested that ancient neutron stars isolated in the solar environment could be heated by dark matter capture, increasing their temperature by 2000 K. Once older than 10 million years, isolated neutron stars are expected to cool to temperatures below this unless reheated by standard matter accretion or internal heating mechanisms.

Recently, it has been suggested that ancient neutron stars isolated in the solar environment could be heated by dark matter capture, increasing their temperature by 2000 K. Once older than 10 million years, isolated neutron stars are expected to cool to temperatures below this unless reheated by standard matter accretion or internal heating mechanisms. As a result, observations of local neutron stars may place severe constraints on dark matter interactions. Importantly, neutron stars with temperatures in this range produce near-infrared radiation that could be detected by future telescopes. “Our new calculations show for the first time that most of the energy is stored in just a few days,” said the study’s lead author, Professor Nicole Bell from the University of Melbourne. “The search for dark matter is one of the greatest detective stories in the history of science.” “Dark matter makes up 85% of the matter in the universe, but we can’t see it.” “It doesn’t interact with light. It doesn’t absorb, reflect, or emit light.” “This means that even if we know it exists, we can’t directly observe it with our telescopes.” “Rather, its attraction to objects that we can see tells us that it must be there.” This could either heat the old, cold neutron star to levels achievable in future observations, or cause the star to collapse into a black hole, he said. University of Melbourne. candidate Michael Vilgat, co-author of the research paper. “If energy transfer occurs fast enough, the neutron star heats up.” “For this to happen, the dark matter must undergo many collisions within the star, transferring more and more dark matter energy until finally all the energy is stored in the star.” “Until now it was unknown how long this process takes, because the lower the energy of the dark matter particles, the less likely they are to interact again.” “So all the energy transfer was thought to take a very long time, in some cases longer than the age of the universe.” Instead, the researchers calculated that 99% of the energy is transferred in just a few days. “This is good news because it means dark matter can potentially heat neutron stars to detectable levels,” Birgat said. “As a result, observations of cold neutron stars will provide important information about the interactions between dark matter and ordinary matter and shed light on the nature of this elusive matter.”

source: https://iopscience.iop.org/article/10.1088/1475-7516/2024/04/006