A recent study explores the potential of binary neutron star-black hole (NSBH) mergers to constrain the equation of state (EoS) of neutron star matter. Unlike binary neutron star (BNS) mergers, where the observed tidal deformability is a combined effect of both stars, NSBH events allow for a direct measurement of the individual neutron star's tidal deformability. This deformation is a direct imprint of the EoS and, consequently, of the internal composition of the neutron star.

The researchers utilized the Bilby parameter estimation computational framework to perform Bayesian inference on hundreds of simulated NSBH mergers. They analyzed these events using current and future gravitational wave detector networks, such as the Einstein Telescope and Cosmic Explorer. The goal was to determine the feasibility of measuring the "bare" tidal deformability of a neutron star with the precision required to distinguish between different EoS models.

The study's findings suggest that at least 20 NSBH merger events, detected by future gravitational wave observatories, will be necessary to clearly differentiate between various equations of state for neutron star matter. This discriminatory capability is crucial for understanding the extreme physics governing the interior of these compact objects, where matter exists at densities and pressures unattainable in any terrestrial laboratory.