Initialising ...
Initialising ...
Initialising ...
Initialising ...
Initialising ...
Initialising ...
Initialising ...
Maruyama, Toshiki
Acta Astronomica Sinica, 56(Suppl.), p.40 - 42, 2015/11
We discuss the effects of inhomogeneous structure of nuclear matter in neutron stars. The inhomogeneous matter due to the first-order phase transition is widely studied. Its effect on the bulk properties are often reported to be minor. However, we stress that the chemical compositions largely affected by the inhomogeneous structures.
Noda, Tsuneo*; Yasutake, Nobutoshi*; Hashimoto, Masaaki*; Maruyama, Toshiki; Tatsumi, Toshitaka*; Fujimoto, Masayuki*
Acta Astronomica Sinica, 56(Suppl.), p.52 - 54, 2015/11
We show a scenario for the cooling of compact stars considering the central source of Cassiopeia A (Cas A). The Cas A observation shows that the central source is a compact star with high effective temperature, and it is consistent with the cooling without exotic phases. The Cas A observation also gives the mass range of 
. It may conflict with the current cooling scenarios of compact stars that heavy stars show rapid cooling. We include the effect of the color superconducting (CSC) quark matter phase on the thermal evolution of compact stars. We assume the gap energy of CSC quark phase is large (
MeV), and we simulate the cooling of compact stars. We present cooling curves obtained from the evolutionary calculations of compact stars: while heavier stars cool slowly, and lighter ones indicate the opposite tendency.
Muto, Takumi*; Maruyama, Toshiki; Tatsumi, Toshitaka*
Acta Astronomica Sinica, 56(Suppl.), p.43 - 45, 2015/11
Coexistence of kaon condensation and hyperons, which may be realized in neutron stars, is investigated on the basis of the relativistic mean-field theory combined with the effective chiral Lagrangian. It is shown that kaon-condensed phase in hyperon-mixed matter is plausible, but it leads to significant softening of the equation of state (EOS). We discuss indispensable effects which make the EOS stiffer so as to be consistent with recent neutron-star observations.
Yasutake, Nobutoshi*; Benic, S.*; Blaschke, D.*; Maruyama, Toshiki; Tatsumi, Toshitaka*
Acta Astronomica Sinica, 56(Suppl.), p.85 - 87, 2015/11
We study quark-hadron phase transition in neutron stars. The finite-size effects of mixed-phase structure should be taken into account in the phase transition of multi-component system. The phase transition strongly depends on the models for quark and hadron matter, surface tension, neutrino fraction, and temperature. We find that with strong surface tension the equation of state (EOS) becomes similar to that of a Maxwell construction, while weak surface tension yields bulk Gibbs condition. We also find that the mass-radius relation obtained by our EOS is consistent to the observation.