A critical test of stellar evolution and convective core ‘overshooting’ by means of ζ Aurigae systems
A critical test of stellar evolution and convective core ‘overshooting’ by means of ζ Aurigae systems
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DOI：
10.1093/mnras/285.4.696
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发表时间：
1997-03
影响因子：
4.8
通讯作者：
K. Schröder;O. Pols;P. Eggleton
中科院分区：
文献类型：
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作者：
K. Schröder;O. Pols;P. Eggleton
定量测试后期恒星演化的计算模型与我们的进化代码，以匹配某些御夫座食双星和相关的非食系统的确切属性。这些双星有一个晚型巨星或超巨星的主星，它们的轨道倾角可以通过日食或斑点轨道很好地确定。它们提供了对这些演化恒星质量的唯一直接测量，以及其他确定的物理参数。在计算中，在中心氢燃烧阶段，对流核心以外的增强混合的所有影响，例如，核心过冲和任何旋转诱导的经向混合都由简单的过冲处方表示。它的单个参数可以限制在其值的25%以内，并导致2.5 M水柱的超调长度lov为0.24 HP（压力刻度高度），6.5 M水柱的超调长度lov略微增加到0.32 HP。我们的代码需要这些值来重现巨星在蓝环中或蓝环末端的确定光度。这种新方法提供了目前最灵敏的过冲问题的测试。
Quantitative tests of late stellar evolution are presented by computing models with our evolutionary code to match the exact properties of certain ζ Aurigae eclipsing binaries and related non-eclipsing systems. Those binaries have a late-type giant or supergiant primary and their orbital inclination is well determined from either eclipses or speckle orbits. They provide the only direct measurements of masses for such evolved stars, together with other well-determined physical parameters.In the computations all effects of enhanced mixing beyond the convective cores during central hydrogen burning stages, e.g., core overshooting and any rotationally induced meridional mixing, are represented by a simple overshooting prescription. Its single parameter can be constrained to within 25 per cent of its value and leads to an overshooting lengthlovof ∼ 0.24HP(pressure scaleheights) for 2.5 M⊙, slightly increasing to ∼ 0.32HPfor 6.5 M⊙. Those values are required by our code to reproduce the well-determined luminosities of the giants in or at the end of their blue loop. This new method provides the currently most sensitive test of the overshooting issue.