Abstract

We present the results of determination of the age, helium mass fraction (Y), metallicity ([Fe/H]), and abundances of the elements C, O, Na, Mg, Ca, Ti, Cr and Mn for 26 globular clusters of the Galaxy. In this work, we apply a method developed by us that employs medium-resolution integrated-light spectra of globular clusters and models of stellar atmospheres and it is supplemented in this paper by the automatic calculation of microturbulence velocities of stars in the studied objects. Based on the data obtained for 26 objects, as well as the results of our previous studies, it is shown that the abundances of chemical elements that we measured, with the exception of carbon, are consistent with the literature estimates from the analysis of integrated-light spectra of clusters and from high-resolution spectroscopic observations of their brightest stars. Our estimates of [C/Fe] are consistent with the literature values obtained from the integrated-light spectra of clusters. We interpret the systematic difference between the derived [C/Fe] for globular clusters and the literature [C/Fe] values for the brightest stars of the clusters as a change of the chemical composition in the atmospheres of stars during their evolution. The estimated absolute ages and average Y for the clusters are in a reasonable agreement with the literature data from the analysis of color–magnitude diagrams of the objects.

中文翻译：

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银河系球状星团的积分光光谱分析

摘要

我们提供年龄，氦质量分数（Y），金属性（[Fe / H]）和银河系26个球状星团中元素C，O，Na，Mg，Ca，Ti，Cr和Mn的丰度。在这项工作中，我们采用了我们开发的一种方法，该方法利用球状星团的中等分辨率积分光谱和恒星大气模型，并通过自动计算被研究物体中恒星的微湍流速度对其进行了补充。根据从26个物体获得的数据以及我们以前的研究结果，可以看出，我们测得的除碳以外的化学元素的丰度与综合分析得出的文献估计相符。团簇的光谱和最亮恒星的高分辨率光谱观察。我们对[C / Fe]的估计与从团簇的集成光谱获得的文献值一致。我们将球状星团的导出的[C / Fe]与星团中最亮的恒星的文献[C / Fe]值之间的系统差异解释为恒星演化过程中恒星大气中化学成分的变化。估计的绝对年龄和平均年龄通过对物体色度图的分析，聚类的Y与文献数据是合理一致的。