标题： 由A型星中原子扩散引起的流体动力学不稳定性及其后果 显示英文标题

标题： Hydrodynamical instabilities induced by atomic diffusion in A stars and their consequences

摘要： 目标。 原子扩散，包括辐射加速度对单个元素的影响，会导致恒星内部化学成分的重要变化。 元素在特定层中的积累，这些元素是局部不透明度的主要贡献者，会导致流体动力学不稳定，从而改变内部恒星结构和表面丰度。 我们的目标是研究这些效应，并将产生的表面丰度与光谱观测进行比较方法。 我们计算了包括这些效应的A型恒星的详细结构。 我们使用了图卢兹-日内瓦演化代码（TGEC），其中辐射加速度使用单值参数（SVP）方法计算，并添加了由三维（3D）模拟得出的双扩散对流，具有混合系数。 结果。 我们表明初始化学成分的修改对内部恒星混合有重要影响，并导致元素的不同表面丰度。 如果由双扩散对流单独混合的层相互连接，则结果与观测到的表面化学成分很好地吻合。 显示英文摘要

摘要： Aims. Atomic diffusion, including the effect of radiative accelerations on individual elements, leads to important variations of the chemical composition inside the stars. The accumulation in specific layers of the elements, which are the main contributors of the local opacity, leads to hydrodynamical instabilities that modify the internal stellar structure and surface abundances. Our aim is to study these effects and compare the resulting surface abundances with spectroscopic observations Methods. We computed the detailed structure of A-type stars including these effects. We used the Toulouse-Geneva Evolution Code (TGEC), where radiative accelerations are computed using the Single Valued Parameter (SVP) method, and we added double-diffusive convection with mixing coefficients deduced from three-dimensional (3D) simulations. Results. We show that the modification of the initial chemical composition has important effects on the internal stellar mixing and leads to different surface abundances of the elements. The results fit the observed surface chemical composition well if the layers, which are individually mixed by double-diffusive convection, are connected.