2024-09-26 05:44:27
The cores of neutron stars contain what can still be considered matter as we understand it, albeit at the highest densities achieved in our current universe, with up to two solar masses of matter compressed within a sphere 25 kilometers in diameter.
Beyond this level of density, a black hole is created, from which nothing, not even light, can escape, and which raises many questions about the nature of what is inside.
In more ways than one, neutron stars can be thought of as giant atomic nuclei. In fact, gravity compresses matter within them to densities far exceeding those of individual protons and neutrons.
These densities make neutron stars highly interesting objects for particle physics. A long-standing mystery is whether the immense central pressure of neutron stars can compress protons and neutrons into an exotic phase of matter known as cold quark matter. In this exotic state of matter, individual protons and neutrons no longer exist. Instead, the quarks and gluons that compose them are released from their typical confinement and can move almost freely.
An international team including Eemeli Annala and Aleksi Vuorinen of the University of Helsinki in Finland has for the first time provided a quantitative estimate of the probability of neutron star cores made mostly of quark matter.
The authors of the study have shown that, according to current astrophysical observations, quark matter is almost inevitable in the cores of the most massive neutron stars. The quantitative estimate places the probability at between 80 and 90 percent. This result was arrived at by extensive supercomputer calculations.
The small remaining probability (10-20%) that all neutron stars are composed solely of matter made up of atomic nuclei (essentially, neutrons) requires that the change from nuclear matter to quark matter be a first-order phase transition, similar to liquid water turning into ice.
Such a rapid change in the properties of matter in a neutron star could destabilize the star to such an extent that the formation of even a tiny core of quark matter would cause the star to collapse into a black hole. There would therefore be no stars with quark cores because they would immediately become black holes.
Fuente: : NCYT de Amazings