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野田 常雄*; 橋本 正章*; 松尾 康秀*; 安武 伸俊*; 丸山 敏毅; 巽 敏隆*
JPS Conference Proceedings (Internet), 14, p.020805_1 - 020805_3, 2017/02
被引用回数:0 パーセンタイル:0.03(Astronomy & Astrophysics)A neutron star is a highly dense object which lasts after a supernova explosion. The density of a neutron star overcomes the nuclear density, and the temperature is high at the beginning of its history. An isolated neutron star does not have any heat sources, and it cools down emitting thermal energy by neutrinos. The neutrino emission process depends on the state of interior matter of the neutron star. To compare theoretical simulations and observations of neutron stars, it can constrain the nuclear theory of high density region. We create a model of neutron stars with colour superconducting quark matter and nucleon super fluidity / superconductivity, to satisfy recent observations, including two 2 neutron stars. We parameterize these super-states and demonstrate the cooling curves, which show heavy stars do not always cool faster than lighter stars.
野田 常雄*; 安武 伸俊*; 橋本 正章*; 丸山 敏毅; 巽 敏隆*; 藤本 正行*
Acta Astronomica Sinica, 56(Suppl.), p.52 - 54, 2015/11
コンパクト星の冷却シナリオを示す。カシオペアA(Cas A)の観測により中央のソースは高い有効温度のコンパクト星で、エキゾチックな相を持たない場合の冷却と矛盾しない。Cas Aの観測データから、Cas Aの質量が太陽質量の1.5倍以上となることが分かる。それは重いコンパクト星ほど早く冷えるという現在のコンパクト星の冷却シナリオと矛盾する可能性がある。我々はコンパクト星の冷却にカラー超伝導のあるクォーク物質の効果を入れ、ギャップエネルギーが10MeVより大きいと仮定した。冷却曲線を計算すると、重い星はゆっくり冷えて軽い星はその反対の傾向を持つことを示した。
野田 常雄*; 橋本 正章*; 安武 伸俊*; 丸山 敏毅; 巽 敏隆*; 藤本 正行*
Astrophysical Journal, 765(1), p.1_1 - 1_5, 2013/03
被引用回数:32 パーセンタイル:66.33(Astronomy & Astrophysics)The Cas A observation shows that the central source is a compact star that has high effective temperature, and it is consistent with the cooling without exotic phases. The observation also gives the mass range of , which may conflict with the current plausible cooling scenario of compact stars. There are some cooled compact stars such as Vela or 3C58, which can not be explained by the minimal cooling scenario with the neutrino emission by nucleon superfluidity (PBF). Then we invoke the exotic cooling processes where heavier stars cool faster than lighter ones. However, the result is inconsistent with the observation of Cas A. Therefore, we present a new cooling scenario by constructing models that include a quark color superconducting (CSC) phase with a large energy gap; this phase appears at ultrahigh density regions and reduces neutrino emissivity. In our model, a compact star has a CSC quark core with a low neutrino emissivity surrounded by high emissivity region made by normal quarks. Our result without considering nucleon superfluidity, shows that while heavier stars cool slowly and lighter ones quickly. Furthermore, we show that our scenario is consistent with the recent observations of the effective temperature of Cas A during the last 10 years, including nucleon superfluidity.