标题： 铁和镍在亚矮星B中的扩散 显示英文标题

标题： Iron and nickel diffusion in subdwarf B stars

摘要： 脉动在亚矮星B型恒星中归因于恒星包层中铁族元素的辐射浮力。 到目前为止，用于sdB地震学的恒星模型中仅考虑了铁的扩散。 然而，镍也被认为是驱动脉动模式的不透明度峰的贡献者之一。 包括时间依赖性原子扩散的恒星模型，如我们此处计算的模型，对于评估不同铁族元素对模式驱动的重要性是必要的。 我们进行了氢、氦、碳、氮、氧、氖、镁、铁和镍的辐射加速度的详细计算，并将这些包含在Burgers的扩散方程中。 我们计算了一个典型亚矮星B型恒星的演化和非绝热脉动。 我们表明，尽管其初始丰度较低，镍在sdB包层中的质量分数可以与铁相媲美。 为了准确确定脉动频率和模式不稳定性，必须在恒星模型中包括这两种金属的扩散。 其他铁族元素的作用仍有待评估。 显示英文摘要

摘要： Pulsations in subdwarf B stars are attributed to radiative levitation of iron-group elements in the stellar envelope. Until now, only iron diffusion is accounted for in stellar models used for sdB seismology. However, nickel has also been suggested as a contributor to the opacity bump that drives the pulsation modes. Stellar models including time-dependent atomic diffusion, as we compute here, are needed to evaluate the importance of different iron-group elements for mode driving. We perform detailed calculations of radiative accelerations of H, He, C, N, O, Ne, Mg, Fe and Ni and include these in Burgers' diffusion equations. We compute the evolution and non-adiabatic pulsations of a typical subdwarf B star. We show that, despite its lower initial abundance, nickel accumulates to comparable mass fractions as iron in the sdB envelope. For accurate determination of pulsation frequencies and mode instability, it is essential that diffusion of both metals are included in stellar models. The role of other iron-group elements remain to be evaluated.