论文标题
超子体积粘度和$ r $ - 中子星的模型
Hyperon bulk viscosity and $r$-modes of neutron stars
论文作者
论文摘要
我们提出并应用了修改后的手性有效模型的新参数化，以在相对论平均场理论的框架中研究具有超子核心的旋转中子恒星。在模型中包含间隔的交叉耦合已改善了对称能坡参数的密度含量，这与最近的陆地实验的发现一致。分析了Hyperonic培养基的大量粘度，以研究其在抑制重力驱动的$ r $ modes中的作用。计算了由非lectonic弱相互作用和相应的阻尼时间标准引起的超声散装粘度系数，并获得了$ r $ - 模式的不稳定性窗口。本模型预测，由于振荡的更有效阻尼，不稳定区域会大大减少。我们发现，从$ \ sim 10^8 $ k到$ \ sim 10^{9} $ k，超声散装粘度完全抑制了$ r $ - modes，导致不稳定窗口之间的稳定区域。我们的分析表明，不稳定性可以将星星的角速度降低到$ \ sim $ 0.3〜 $ω_k$，其中$ω_k$是恒星的开普勒频率。
We propose and apply a new parameterization of the modified chiral effective model to study rotating neutron stars with hyperon cores in the framework of the relativistic mean-field theory. The inclusion of mesonic cross couplings in the model has improved the density content of the symmetry energy slope parameters, which are in agreement with the findings from recent terrestrial experiments. The bulk viscosity of the hyperonic medium is analyzed to investigate its role in the suppression of gravitationally driven $r$-modes. The hyperonic bulk viscosity coefficient caused by non-leptonic weak interactions and the corresponding damping timescales are calculated and the $r$-mode instability windows are obtained. The present model predicts a significant reduction of the unstable region due to a more effective damping of oscillations. We find that from $\sim 10^8$ K to $\sim 10^{9}$ K, hyperonic bulk viscosity completely suppresses the $r$-modes leading to a stable region between the instability windows. Our analysis indicates that the instability can reduce the angular velocity of the star up to $\sim$0.3~$Ω_K$, where $Ω_K$ is the Kepler frequency of the star.
