论文标题
早期型恒星和白色矮人的潮汐耗散物理学：内部重力波的流体动力学模拟在恒星信封中破裂
Physics of Tidal Dissipation in Early-Type Stars and White Dwarfs: Hydrodynamical Simulations of Internal Gravity Wave Breaking in Stellar Envelopes
论文作者
论文摘要
在由早期型恒星或白矮星组成的二进制物中，主要的潮汐过程涉及内部重力波（IGWS）的激发，该引发向恒星表面传播及其通过非线性波破裂的消散。我们在分层的等温大气中对此波破裂过程进行了2D流体动力学模拟。我们发现，在初始瞬态阶段之后，IGW的耗散自然会产生尖锐的临界层，将下部固定区域（无平均流量）分开，并且上部“同步”区域（平均流速等于水平波相位速度）。尽管这些波的吸收使临界层陡峭，但它也通过开尔文 - 赫尔姆霍尔茨的不稳定性在稳定状态下宽扩大，以便在稳定状态下，临界层宽度由理查森（Richardson）标准确定。我们研究了临界层的入射波的吸收和反射，并提供了描述其长期演化的分析公式。这项研究的结果对于表征潮汐加热的白色矮人和其他二元星的演变很重要。
In binaries composed of either early-type stars or white dwarfs, the dominant tidal process involves the excitation of internal gravity waves (IGWs), which propagate towards the stellar surface, and their dissipation via nonlinear wave breaking. We perform 2D hydrodynamical simulations of this wave breaking process in a stratified, isothermal atmosphere. We find that, after an initial transient phase, the dissipation of the IGWs naturally generates a sharp critical layer, separating the lower stationary region (with no mean flow) and the upper "synchronized" region (with the mean flow velocity equal to the horizontal wave phase speed). While the critical layer is steepened by absorption of these waves, it is simultaneously broadened by Kelvin-Helmholtz instabilities such that, in steady state, the critical layer width is determined by the Richardson criterion. We study the absorption and reflection of incident waves off the critical layer and provide analytical formulae describing its long-term evolution. The result of this study is important for characterizing the evolution of tidally heated white dwarfs and other binary stars.
