Speaker
Description
The observation of the gravitational-wave signal GW170817 from a binary neutron-star merger marked the beginning of a new era in astrophysics. Such events offer unique opportunities to probe the properties of matter under conditions so extreme that they cannot be reproduced in terrestrial laboratories. During the inspiral phase, neutron stars undergo slight deformations induced by the tidal field of their companion. These deformations are quantified by the so‑called tidal deformabilities. With the advent of third‑generation detectors, tidal deformabilities are expected to be measured with far greater precision, motivating the development of more accurate tidal models that incorporate richer microphysics.
Most existing calculations of tidal deformabilities rely on a cold, barotropic, perfect‑fluid description of neutron‑star matter. In this talk, I will discuss how to go beyond this approximation by including both superfluidity and finite‑temperature effects. Neutrons in the core and in the inner crust are indeed expected to be superfluid, while protons are superconducting in the core. Additionally, neutron‑star matter is likely to heat up during the late inspiral because of tidal friction. Although these two aspects may appear physically distinct, they can be naturally incorporated within a unified multifluid hydrodynamic formalism. Using this framework, I will show how superfluidity and finite temperature impacts the tidal deformabilities of neutron stars.