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首页> 外文期刊>Astronomy and astrophysics >Beryllium abundances along the evolutionary sequence of the open cluster IC?4651 – A new test for hydrodynamical stellar models
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Beryllium abundances along the evolutionary sequence of the open cluster IC?4651 – A new test for hydrodynamical stellar models

机译：沿开放簇IC？4651的进化序列的铍丰度–流体力学恒星模型的新测试

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Context. Previous analyses of lithium abundances in mainsequence and red giant stars have revealed the action of mixingmechanisms other than convection in stellar interiors. Berylliumabundances in stars with Li abundance determinations can offer valuablecomplementary information on the nature of these mechanisms. Aims. Our aim is to derive Be abundances along the wholeevolutionary sequence of an open cluster. We focus on the well-studiedopen cluster IC4651. These Be abundances are used with previouslydetermined Li abundances, in the same sample stars, to investigate themixing mechanisms in a range of stellar masses and evolutionary stages.Methods. Atmospheric parameters were adopted from a previousabundance analysis by the same authors. New Be abundances have beendetermined from high-resolution, high signal-to-noise UVES spectrausing spectrum synthesis and model atmospheres. The careful syntheticmodeling of the Be lines region is used to calculate reliableabundances in rapidly rotating stars. The observed behavior of Be andLi is compared to theoretical predictions from stellar models includingrotation-induced mixing, internal gravity waves, atomic diffusion, andthermohaline mixing. Results. Beryllium is detected in all the main sequence andturn-off sample stars, both slow- and fast-rotating stars, includingthe Li-dip stars, but is not detected in the red giants. Confirmingprevious results, we find that the Li dip is also a Be dip, althoughthe depletion of Be is more modest than for Li in the correspondingeffective temperature range. For post-main-sequence stars, the Bedilution starts earlier within the Hertzsprung gap than expected fromclassical predictions, as does the Li dilution. A clear dispersion inthe Be abundances is also observed. Theoretical stellar modelsincluding the hydrodynamical transport processes mentioned above areable to reproduce all the observed features well. These results show agood theoretical understanding of the Li and Be behavior along thecolor-magnitude diagram of this intermediate-age cluster for stars moremassive than 1.2.Key words: stars: abundances - stars: evolution - rotation - open clusters and associations: individual: IC 4651
机译：上下文。先前对主序列和红色巨星中锂丰度的分析表明，恒星内部的对流作用不同于混合机制。锂含量确定的恒星中的铍含量可以提供有关这些机理性质的有价值的补充信息。目的我们的目标是沿开放星团的整个进化序列推导Be丰度。我们专注于研究透彻的开放式集群IC4651。这些Be丰度与先前确定的Li丰度在同一颗样本恒星中一起使用，以研究一系列恒星质量和演化阶段的混合机制。同一作者先前的丰度分析采用了大气参数。使用光谱合成和模型大气，已从高分辨率，高信噪比的UVES光谱中确定了新的Be丰度。 Be线区域的仔细合成模型用于计算快速旋转恒星中的可靠丰度。将Be和Li的观察到的行为与恒星模型的理论预测进行比较，这些恒星模型包括旋转诱导的混合，内部重力波，原子扩散和热盐混合。结果。在所有主序和熄灭样本恒星中都检测到铍，包括慢速旋转恒星和快速旋转恒星，包括浸锂星，但在红色巨星中均未检测到。确认先前的结果，我们发现Li浸蚀也是Be浸蚀，尽管在相应的有效温度范围内，Be的耗损比Li的浸蚀更为适度。对于主序后恒星，与Li稀释一样，Bedilution在Hertzsprung间隙内的开始时间比经典预测所期望的要早。还观察到Be丰度明显分散。理论恒星模型包括上述流体动力传输过程，能够很好地重现所有观察到的特征。这些结果表明，对于这个质量大于1.2的恒星，沿这个中年星团的色度图，对Li和Be行为有很好的理论理解。关键词：恒星：丰度-恒星：演化-自转-开放星团和缔合：个人：IC 4651

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