标题： 47天蝎座白矮星冷却序列 显示英文标题

标题： The white dwarf cooling sequence of 47 Tucanae

摘要： 47 Tucanae 是最有趣且被广泛观测和理论研究的球状星团之一。 这使我们能够研究对白矮星冷却序列理解的可靠性，验证不同的确定其年龄的方法，并评估其他重要特征，如其恒星形成历史。 在这里，我们介绍了球状星团 47 Tucanae 冷却序列的人口合成研究。 特别是，我们研究了有效温度的分布、颜色-光度图的形状以及相应的光度和颜色分布。 我们使用基于蒙特卡罗技术的最新人口合成代码，该代码结合了最新且可靠的冷却序列以及对观测偏差的准确建模。 我们发现理论模型与观测数据之间有良好的一致性。 因此，我们的研究排除了之前关于在中等高温的有效温度下白矮星冷却模型仍存在缺失物理机制的说法。 我们还使用冷却序列的终止来推导该星团的年龄，得到的结果与使用主序星转折点确定的年龄一致。 最后，我们发现该星团的恒星形成历史与使用主序星获得的结果一致，这预测了两个不同种群的存在。 我们得出结论，正确建模球状星团中的白矮星种群，结合主序星的数量计数，提供了一个独特的工具来模拟球状星团的特性。 显示英文摘要

摘要： 47 Tucanae is one of the most interesting and well observed and theoretically studied globular clusters. This allows us to study the reliability of our understanding of white dwarf cooling sequences, to confront different methods to determine its age, and to assess other important characteristics, like its star formation history. Here we present a population synthesis study of the cooling sequence of the globular cluster 47 Tucanae. In particular, we study the distribution of effective temperatures, the shape of the color-magnitude diagram, and the corresponding magnitude and color distributions. We do so using an up-to-date population synthesis code based on Monte Carlo techniques, that incorporates the most recent and reliable cooling sequences and an accurate modeling of the observational biases. We find a good agreement between our theoretical models and the observed data. Thus, our study, rules out previous claims that there are still missing physics in the white dwarf cooling models at moderately high effective temperatures. We also derive the age of the cluster using the termination of the cooling sequence, obtaining a good agreement with the age determinations using the main-sequence turn-off. Finally, we find that the star formation history of the cluster is compatible with that btained using main sequence stars, which predict the existence of two distinct populations. We conclude that a correct modeling of the white dwarf population of globular clusters, used in combination with the number counts of main sequence stars provides an unique tool to model the properties of globular clusters.