标题： 化学平衡的温暖中子星中成分$g$模式的抑制 显示英文标题

标题： Suppression of composition $g$-modes in chemically-equilibrating warm neutron stars

摘要： 我们研究化学平衡化及其导致的体积粘滞对温度高达$T\approx 5$MeV 的温暖中子星的非径向振荡模式的影响，这对于质子中子星和中子星并合后残余物是相关的。 在此范围内，弱相互作用的弛豫率与核心中成分$g$-模的特征频率相当，导致共振阻尼。 为了捕捉这种效应，我们引入了动态声速，这是一种复数、频率依赖的绝热声速的推广，它包含了体积压缩的恢复力和耗散效应。 使用真实的弱反应速率和三种典型的方程状态，我们计算了具有有限温度分布的成分$g$-模的复频率。 我们发现，随着温度的升高，体积粘滞阻尼变得越来越显著，并可以完全抑制成分$g$-模。 相比之下， $f$-模由于其几乎无散度的特性，基本上不受体积粘滞的影响。 我们的结果强调了$g$-模行为对热结构、弱反应速率和方程状态的敏感性，并确立了动态声速作为描述耗散中子星物质振荡特性的有价值的描述符。 显示英文摘要

摘要： We investigate the impact of chemical equilibration and the resulting bulk viscosity on non-radial oscillation modes of warm neutron stars at temperatures up to $T\approx 5$ MeV, relevant for protoneutron stars and neutron-star post-merger remnants. In this regime, the relaxation rate of weak interactions becomes comparable to the characteristic frequencies of composition $g$-modes in the core, resulting in resonant damping. To capture this effect, we introduce the dynamical sound speed, a complex, frequency-dependent generalization of the adiabatic sound speed that encodes both the restoring force and the dissipative effects of bulk compression. Using realistic weak reaction rates and three representative equations of state, we compute the complex frequencies of composition $g$-modes with finite-temperature profiles. We find that bulk viscous damping becomes increasingly significant with temperature and can completely suppress composition $g$-modes. In contrast, the $f$-mode remains largely unaffected by bulk viscosity due to its nearly divergence-free character. Our results highlight the sensitivity of $g$-mode behavior to thermal structure, weak reaction rates, and the equation of state, and establish the dynamical sound speed as a valuable descriptor characterizing oscillation properties in dissipative neutron star matter.