A Finnish research group has found strong evidence for the presence of exotic quark matter inside the cores of the largest neutron stars in existence. They reached this conclusion by combining recent results from theoretical particle and nuclear physics to measurements of gravitational waves from neutron star collisions.
All normal matter surrounding us is composed of atoms, whose dense nuclei, comprising protons and neutrons, are surrounded by negatively charged electrons. However, inside neutron stars, atomic matter is known to collapse into immensely dense nuclear matter in which the neutrons and protons are packed together so tightly that the entire star can be considered one single enormous nucleus.
Up until now, it has remained unclear whether nuclear matter in the cores of the most massive neutron stars collapses into an even more exotic state called quark matter, in which the nuclei themselves no longer exist. Researchers from the University of Helsinki now claim that the answer to this question is yes. The new results were published in Nature Physics.
“Confirming the existence of quark cores inside neutron stars has been one of the most important goals of neutron star physics ever since this possibility was first entertained roughly 40 years ago,” says Associate Professor Aleksi Vuorinen from the University of Helsinki’s Department of Physics.
Existence very likely
With even large-scale simulations run on supercomputers unable to determine the fate of nuclear matter inside neutron stars, the Finnish research group proposed a new…