Age and helium content of the open cluster NGC 6791 from multiple eclipsing binary members: III. Constraints from a subgiant
Age and helium content of the open cluster NGC 6791 from multiple eclipsing binary members: III. Constraints from a subgiant
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来自多个食双星成员的疏散星团 NGC 6791 的年龄和氦含量：III。
DOI：
10.1051/0004-6361/202140911
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发表时间：
2021
影响因子：
6.5
通讯作者：
Sørensen, C. T.
中科院分区：
文献类型：
--
作者：
Brogaard, K.;Grundahl, F.;Sandquist, E. L.;Slumstrup, D.;Jensen, M. L.;Thomsen, J. B.;Jørgensen, J. H.;Larsen, J. R.;Bjørn, S. T.;Sørensen, C. T.
恒星结构和演化的模型可以通过对疏散星团食双星成员参数的精确测量来约束。多颗联星提供了收紧约束的方法，从而提高了主星系团年龄估计的精确度和准确度。在本系列的前两篇论文中，我们已经证明了使用老疏散星团NGC 6791中的多个食双星的测量来对恒星模型的性质设置比以前更严格的约束，从而提高了星团年龄的准确性和精确度。方法结合NGC6971中食双星的测光和测量结果，分析FLAMES中V56的多历元光谱。结果发现V56组分的参数为Mp = 1 0.103 ± 0.008M ε，Ms = 0.974 ± 0.007M ε，Rp = 1.764 ± 0.099R ε，Rs = 1.045 ± 0.057R ε，Teff，p = 5447 ± 125 K，Teff，s = 5552 ± 125 K，表面[Fe/H]=+0.29 ± 0.06.结论所得结果加强了我们先前对星团年龄的最佳估计（8.3 ± 0.3Gy r和较低的红巨星分支上的恒星质量（RGB），对于NGC 6791，MRGB = 1.15 ± 0.02 M质量。 因此，这些数字继续作为其他年龄和质量测量方法（如星震学）的验证点。
ContextModels of stellar structure and evolution can be constrained using accurate measurements of the parameters of eclipsing binary members of open clusters. Multiple binary stars provide the means to tighten the constraints and, in turn, to improve the precision and accuracy of the age estimate of the host cluster. In the previous two papers of this series, we have demonstrated the use of measurements of multiple eclipsing binaries in the old open cluster NGC 6791 to set tighter constraints on the properties of stellar models than was previously possible, thereby improving both the accuracy and precision of the cluster age.AimsWe identify and measure the properties of a non-eclipsing cluster member, V56, in NGC 6791 and demonstrate how this provides additional model constraints that support and strengthen our previous findings.MethodsWe analyse multi-epoch spectra of V56 from FLAMES in conjunction with the existing photometry and measurements of eclipsing binaries in NGC6971.ResultsThe parameters of the V56 components are found to beMp= 1.103 ± 0.008M⊙andMs= 0.974 ± 0.007M⊙,Rp= 1.764 ± 0.099R⊙andRs= 1.045 ± 0.057R⊙,Teff,p= 5447 ± 125 K andTeff,s= 5552 ± 125 K, and surface [Fe/H] = +0.29 ± 0.06 assuming that they have the same abundance.ConclusionsThe derived properties strengthen our previous best estimate of the cluster age of 8.3 ± 0.3 Gyr and the mass of stars on the lower red giant branch (RGB), which isMRGB= 1.15 ± 0.02M⊙for NGC 6791. These numbers therefore continue to serve as verification points for other methods of age and mass measures, such as asteroseismology.