Cooling of Isolated Neutron Stars with Pion Condensation: Possible Fast Cooling in a Low-Symmetry-Energy Model
arXiv:2112.13302 · doi:10.1142/S0218301322500069
Abstract
We studied thermal evolution of isolated neutron stars (NSs) including the pion condensation core, with an emphasis on the stiffness of equation of state (EOS). Many temperature observations can be explained by the minimal cooling scenario which excludes the fast neutrino cooling process. However, several NSs are cold enough to require it. The most crucial problem for NS cooling theory is whether the nucleon direct Urca (DU) process is open. The DU process is forbidden if the nucleon symmetry energy is significantly low. Hence, another fast cooling process is required in such an EOS. As the candidate to solve this problem, we consider the pion condensation. We show that the low-symmetry-energy model can account for most cooling observations including cold NSs, with strong neutron superfluidity. Simultaneously, it holds the observations even if the pion condensation core exists. Thus, we propose the possibility of pion condensation, as an exotic state to solve the problem in low-symmetry-energy EOSs. We examined the consistency of our EOSs with other various observations as well.
21 pages, 8 figures, accepted by Int. J. Mod. Phys. E
References in corpus (14)
- GW170817: Observation of Gravitational Waves from a Binary Neutron Star Inspiral
- Shapiro delay measurement of a two solar mass neutron star
- A Massive Pulsar in a Compact Relativistic Binary
- PSR J0030+0451 Mass and Radius from NICER Data and Implications for the Properties of Neutron Star Matter
- Constraints on the Symmetry Energy Using the Mass-Radius Relation of Neutron Stars
- Density dependence of the nuclear symmetry energy: a microscopic perspective
- Nuclear equation of state for core-collapse supernova simulations with realistic nuclear forces
- Screening Effects in Superfluid Nuclear and Neutron Matter within Brueckner Theory
- Tests of the nuclear equation of state and superfluid and superconducting gaps using the Cassiopeia A neutron star
- Was GW170817 a canonical neutron star merger? Bayesian analysis with a third family of compact stars
- Equation of state of low--density neutron matter and the pairing gap
- Occurrence of Hyperon Superfluidity in Neutron Star Cores
- An X-ray Search for Compact Central Sources in Supernova Remnants II: Six Large Diameter SNRs
- Possibility of rapid neutron star cooling with the realistic equation of state