Thermal evolution of neutron stars described within the equation of state with induced surface tension

Abstract

We present a modeling of the thermal evolution of the neutron stars, incorporating an effect of neutron and proton pairing. The considered equation of state with induced surface tension (IST) reproduces properties of normal nuclear matter, fulfills the proton flow constraint, provides a high-quality description of particle yields created in heavy-ion collisions, and is equally compatible with the constraints from astrophysical observations and the GW170817 event. The model features strong direct Urca processes for the stars above 1.91 M ⊙. Our results show a very good agreement with the available cooling data, including observational data of the compact object in the center of the Cassiopeia A (Cas A), even without introducing nuclear pairing. The rapid cooling rate of the Cas A can be also reproduced by a 1.66 M ⊙ star with an atmosphere of light elements, high-mass 1.955 − 1.96 M ⊙ stars with paired and unpaired matter, as well as by a 1.91 M ⊙ star with inclusion of neutron and proton pairings in the singlet channel.

The Impact of Asymmetric Dark Matter on the Thermal Evolution of Nucleonic and Hyperonic Compact Stars

“…[135], the IST EoS does not necessarily require the incorporation of the neutron superfluidity and/or proton conductivity to explain the Cas A temperature drop. The model reproduced the Cas A data with 1.66 M ⊙ and 1.91 M ⊙ stars with the inclusion of neutron and proton singlet pairings, as well as with the 1.96 M ⊙ star for unpaired matter [136].…”

“…[139], the IST EoS does not necessarily require the incorporation of the neutron superfluidity and/or proton conductivity to explain the Cas A temperature drop. The model reproduced the Cas A data with 1.66 M ⊙ and 1.91 M ⊙ stars with the inclusion of neutron and proton singlet pairings, as well as with the 1.96 M ⊙ star for unpaired matter [140]. As it was shown in [90] the FSU2R EoS describes the Cas A cooling with a combination of n 1 S 0 (SFB model), p 1 S 0 (CCDK model), n 3 P 2 pairing (T72 model) with the maximum critical temperature T c = 7.105 • 10 8 K. In Ref.…”