The effect of temperature on the tidal deformability of neutron stars

The recent detections of gravitational waves, which originated from binary neutron star mergers, offer a unique tool for studying the high-density region of dense nuclear matter. The role of temperature during the inspiral phase of a binary neutron star system is an open possibility, given the fact that there is not at this time evidence for its absence (zero temperature). Moreover, some theoretical studies suggest the existence of temperature, about a few MeV, during the last orbits before the merger. According to theory, friction may be developed in the star leading to the conversion of mechanical energy into heat. This effect might be detectable before the merger. In this work, our main purpose is to study the role of temperature on the tidal deformability of neutron stars, during the final stages of the inspiral phase. In our study, we used a variety of hot equations of state (isothermal and adiabatic) of various nuclear models. We found that for values of temperature below 1 MeV the tidal deformability as a relation to neutron star mass remains insensitive, though its ingredients (e.g. tidal Love number k₂) are affected. Regarding the adiabatic case, the thermal effect is unapparent up to S=0.2k_B. This surprising behavior of tidal deformability is analyzed further. (author)