论文标题
进化的恒星的星星学限制了角动量的内部运输。 V.红色巨型分支和红色集团上运输的效率
Asteroseismology of evolved stars to constrain the internal transport of angular momentum. V. Efficiency of the transport on the red giant branch and in the red clump
论文作者
论文摘要
多亏了星星学,对于进化阶段的数百个低质量和中间质量恒星,对核心旋转速率的限制可用。在恒星进化模型中测试的当前物理过程无法再现这些核心旋转速率的演变。我们根据其核心旋转速率的紫selosisic确定,研究了在氢壳和核心燃烧阶段红色巨人的内部角动量重新分布的效率。我们通过旋转来计算出色的演化模型,并通过通过额外的粘度参数化的唯一显性扩散过程的作用来对角动量的运输进行建模。我们限制了这种粘度的值,以使红色巨人的平均核心旋转速率及其行为及其行为与红色巨型分支和红色团块的质量和进化相匹配。对于氢壳燃烧阶段中的红色巨人,在更大的恒星中,角动量的运输必须更有效。在质量范围M $ \ sim $ 1-2.5 m $ _ {\ odot} $中,额外的粘度在质量范围M $ \ sim $ \ sim $ \ sim中大约有两个数量级变化。随着恒星沿着红色巨型分支的发展,低质量恒星的内部动量效率必须提高(m $ \ lyssim $ 2 m $ _ {\ odot} $),并且对于稍高的质量(2.0 m $ _ {\ odot} $ \ \ odot} $ \ \ messim $ m $ m $ $ 2.5 m $ $ 2.5 m $ _}的质量略高(2.0 m $ _ {\ odot} $ _ {\ odot} $ _)在红卷曲的恒星中,额外的粘度必须比在氢壳燃烧阶段的年轻红色巨人中高的数量级。结合以前的努力,我们清楚地了解了如何在主序列的末端重新分布角度动量,直到低和中间质量恒星的核心螺旋燃烧阶段,以满足小星座抑制剂。
Thanks to asteroseismology, constraints on the core rotation rate are available for hundreds of low- and intermediate-mass stars in evolved phases. Current physical processes tested in stellar evolution models cannot reproduce the evolution of these core rotation rates. We investigate the efficiency of the internal angular momentum redistribution in red giants during the hydrogen shell and core-helium burning phases based on the asteroseismic determinations of their core rotation rates. We compute stellar evolution models with rotation and model the transport of angular momentum by the action of a sole dominant diffusive process parametrized by an additional viscosity. We constrain the values of this viscosity to match the mean core rotation rates of red giants and their behaviour with mass and evolution along the red giant branch and in the red clump. For red giants in the hydrogen shell-burning phase the transport of angular momentum must be more efficient in more massive stars. The additional viscosity is found to vary by approximately two orders of magnitude in the mass range M $\sim$ 1 - 2.5 M$_{\odot}$. As stars evolve along the red giant branch, the efficiency of the internal transport of angular momentum must increase for low-mass stars (M $\lesssim$ 2 M$_{\odot}$) and remain approximately constant for slightly higher masses (2.0 M$_{\odot}$ $\lesssim$ M $\lesssim$ 2.5 M$_{\odot}$). In red-clump stars, the additional viscosities must be an order of magnitude higher than in younger red giants of similar mass during the hydrogen shell-burning phase. In combination with previous efforts, we obtain a clear picture of how the physical processes acting in stellar interiors should redistribute angular momentum from the end of the main sequence until the core-helium burning phase for low- and intermediate-mass stars to satisfy the asteroseismic constraints.