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Ogata, Misa*; Okawa, Hirotada*; Fujisawa, Kotaro*; Yasutake, Nobutoshi; Yamamoto, Yu*; Yamada, Shoichi*
Monthly Notices of the Royal Astronomical Society, 521(2), p.2561 - 2576, 2023/05
Times Cited Count：0 Percentile：0(Astronomy & Astrophysics)Xia, C.-J.*; Maruyama, Toshiki; Yasutake, Nobutoshi*; Tatsumi, Toshitaka*; Zhang, Y.-X.*
Physics Letters B, 839, p.137769_1 - 137769_5, 2023/04
Times Cited Count：1 Percentile：68.16(Astronomy & Astrophysics)Okawa, Hirotada*; Fujisawa, Kotaro*; Yasutake, Nobutoshi; Ogata, Misa*; Yamamoto, Yu*; Yamada, Shoichi*
Monthly Notices of the Royal Astronomical Society, 520(1), p.24 - 43, 2023/03
Times Cited Count：1 Percentile：50.15(Astronomy & Astrophysics)Xia, C.-J.*; Maruyama, Toshiki; Yasutake, Nobutoshi*; Tatsumi, Toshitaka*
Physical Review D, 106(6), p.063020_1 - 063020_14, 2022/09
Times Cited Count：4 Percentile：49.9(Astronomy & Astrophysics)Xia, C.-J.*; Maruyama, Toshiki; Yasutake, Nobutoshi*; Tatsumi, Toshitaka*; Zhang, Y.-X.*
Physical Review C, 103(5), p.055812_1 - 055812_13, 2021/05
Times Cited Count：13 Percentile：90.39(Physics, Nuclear)Xia, C.-J.*; Maruyama, Toshiki; Yasutake, Nobutoshi*; Tatsumi, Toshitaka*; Shen, H.*; Togashi, Hajime*
Physical Review D, 102(2), p.023031_1 - 023031_18, 2020/07
Times Cited Count：16 Percentile：74.34(Astronomy & Astrophysics)no abstracts in English
Maslov, K.*; Yasutake, Nobutoshi*; Blaschke, D.*; Ayriyan, A.*; Grigorian, H.*; Maruyama, Toshiki; Tatsumi, Toshitaka*; Voskresensky, D. N.*
Physical Review C, 100(2), p.025802_1 - 025802_11, 2019/08
Times Cited Count：44 Percentile：97.28(Physics, Nuclear)The effect of pasta phases on the quark-hadron phase transition is investigated for a set of relativistic mean-field equations of state for both hadron and quark matter. The results of the full numerical solution with pasta phases are compared with those of an interpolating construction used in previous works, for which we demonstrate an adequate description of the numerical results. For each pair of quark and hadron matter models the critical value of the surface tension is determined, above which the phase transition becomes close to the Maxwell construction. This result agrees well with earlier theoretical estimates. The study is extended to neutron star matter in beta equilibrium with electrons and muons and is applied to investigate the effect of pasta phases on the structure of hybrid compact stars and the robustness of a possible third family solution.
Lee, T.-G.*; Yasutake, Nobutoshi*; Maruyama, Toshiki; Tatsumi, Toshitaka*
Proceedings of Science (Internet), 281, p.326_1 - 326_8, 2017/05
Noda, Tsuneo*; Hashimoto, Masaaki*; Matsuo, Yasuhide*; Yasutake, Nobutoshi*; Maruyama, Toshiki; Tatsumi, Toshitaka*
JPS Conference Proceedings (Internet), 14, p.020805_1 - 020805_3, 2017/02
Times Cited Count：0 Percentile：0.03(Astronomy & Astrophysics)Lee, T.-G.*; Nishiyama, Kazuya*; Yasutake, Nobutoshi*; Maruyama, Toshiki; Tatsumi, Toshitaka*
JPS Conference Proceedings (Internet), 14, p.020808_1 - 020808_3, 2017/02
Times Cited Count：0 Percentile：0.03(Astronomy & Astrophysics)Yasutake, Nobutoshi*; Chen, H.*; Maruyama, Toshiki; Tatsumi, Toshitaka*
Journal of Physics; Conference Series, 665(1), p.012068_1 - 012068_4, 2016/01
Times Cited Count：6 Percentile：88.68(Astronomy & Astrophysics)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.
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.
Yasutake, Nobutoshi*; Lastowiecki, R.*; Benic, S.*; Blaschke, D.*; Maruyama, Toshiki; Tatsumi, Toshitaka*
Physical Review C, 89(6), p.065803_1 - 065803_10, 2014/06
Times Cited Count：80 Percentile：97.6(Physics, Nuclear)Maruyama, Toshiki; Yasutake, Nobutoshi*; Tatsumi, Toshitaka*
Proceedings of Science (Internet), 146, p.125_1 - 125_6, 2013/04
We explore the inhomogeneous structures and properties of nuclear matter with inclusion of trapped neutrinos which is relevant to the supernovae and the crust of proto-neutron stars. As a theoretical framework we employ the relativistic mean field (RMF) model with the Thomas-Fermi approximation for fermions. In our previous studies of nuclear matter without neutrino, we have observed "pasta" structures in nuclear matter with a fixed electron fraction while there appeared only spherical nuclei in catalyzed nuclear matter. In our present study of catalyzed nuclear matter with a fixed lepton fraction, pasta structures are found to be persistent due to the increase of protonfraction which causes the formation of cluster of protons and neutrons by their strong attraction. We present the equation of state (EOS) of neutrino-trapped nuclear matter and discuss the effects of the existence of neutrinos.
Noda, Tsuneo*; Hashimoto, Masaaki*; Yasutake, Nobutoshi*; Maruyama, Toshiki; Tatsumi, Toshitaka*; Fujimoto, Masayuki*
Astrophysical Journal, 765(1), p.1_1 - 1_5, 2013/03
Times Cited Count：32 Percentile：66.33(Astronomy & Astrophysics)Yasutake, Nobutoshi*; Noda, Tsuneo*; Sotani, Hajime*; Maruyama, Toshiki; Tatsumi, Toshitaka*
Recent Advances in Quarks Research, p.63 - 111, 2013/01
Yasutake, Nobutoshi*; Maruyama, Toshiki; Tatsumi, Toshitaka*
Physical Review D, 86(10), p.101302_1 - 101302_4, 2012/11
Times Cited Count：10 Percentile：38.3(Astronomy & Astrophysics)We have studied hadron-quark mixed phase in protoneutron stars, which is a ternary system, i.e., conserves the total baryon number, total charge, and total lepton number. We found that no crystalline "pasta" structure appears in the regime of high lepton number fraction; the size of pasta structure diverges due to the charge screening and the system becomes mechanically unstable. Consequently the whole system is separated into two bulk regions like an amorphous state, where the surface effect is safely neglected. There, the local charge neutrality is approximately attained, so that the equation of state is effectively reduced to that of a binary system. However, since the lepton-number fraction as well as baryon-number density is different for two phases in the amorphous state, we cannot reduce it to a pure system. Hence, we conclude that there is no possibility of a density discontinuity, which is a specific feature in a pure system, to appear in protoneutron-star matter.
Tatsumi, Toshitaka*; Yasutake, Nobutoshi*; Maruyama, Toshiki
Neutron Stars; The Aspect of High Density Matter, Equations of State and Observables, p.199 - 231, 2012/10
We consider the first-order phase transitions and the phase equilibrium on the basis of the gibbs conditions, taking the liquid-gas phase transition in asymmetric nuclear matter as an example. Characteristic features of the mixed phase are figured out by solving the coupled equations for mean-fields and densities of constituent particles self-consistently. The mixed phase is inhomogeneous matter composed of two phases with characteristic shapes called "pasta". We take into account the coulomb interaction and the interface energy, and thereby sometimes we see the mechanical instability of the mixed phase. Thermal effect on the liquid-gas phase transition is also elucidated. Similarly hadron-quark deconfinement transition is studied in hyperonic matter, where the neutrino-trapping effect as well as the thermal effect is discussed. Specific features of the mixed phase are elucidated and the equation of state is presented.
Yasutake, Nobutoshi*; Maruyama, Toshiki; Tatsumi, Toshitaka*
Journal of Physics; Conference Series, 312, p.042027_1 - 042027_6, 2011/09
Times Cited Count：9 Percentile：93.4(Astronomy & Astrophysics)We study the quark-hadron mixed phase in protoneutron stars with the finite-size effects. In the calculations of pasta structures appeared in the mixed phase, the Gibbs conditions require the pressure balance and chemical equilibrium between two phases besides the thermal equilibrium. We find that the region of the mixed phase is limited due to thermal instability. Moreover, we study the effects of neutrinos to the pasta structures. As a result, we find that the existence of neutrinos make the pasta structures unstable, too. These characteristic features of the hadron-quark mixed phase should be important for the middle stage of the evolutions of protoneutron stars.
