论文标题
部分可观测时空混沌系统的无模型预测
Distance and age of the massive stellar cluster Westerlund 1. II. The eclipsing binary W36
论文作者
论文摘要
Westerlund 1（WD 1）是银河系中最相关的恒星簇之一，尽管仍然鲜为人知，但研究大规模的恒星形成。在这里，我们使用光度法和光谱数据来对黯然失色的二进制W36进行建模，表明其光谱类型为O6.5 III + O9.5 IV，比以前想象的更热，更发光。它的距离$ d _ {\ rm w36} $ $ = $ 4.03 $ \ $ $ 0.25 kpc在错误中同意，在论文I，Beasor＆Davies和negueruela的小组中，最近有三个基于GAIA-EDR3的距离。但是，他们遵循不同的方法来修复红色源的零点，例如WD 1中的源并选择最佳方法，我们使用了W36的准确建模。我们的视差（纸I）和二进制距离的加权平均距离会导致$ d _ {\ rm WD1} $ = 4.05 $ \ pm $ 0.20 kpc，其前所未有的准确性为5％。我们根据日内瓦代码采用了同句，并具有超级极丰度，将W36B的年龄推断为6.4 $ \ pm $ 0.7 MYR。这个物体似乎是OB巨人和超级巨头代表的多产之星形成爆发的一部分，其发生在7.1 $ \ pm $ 0.5 MYR AGO，这与最近出版的PMS等速线伴随着7.2岁的Myr相吻合。其他BA型发光的恒星和黄色超级恒星的年龄范围为8--11 Myr。在论文中讨论的四个红色超级巨人代表了该集群中最古老的人口，年龄为10.7 $ \ pm $ 1 MYR。 WD 1中的恒星形成的多个发作让人联想到R136/30 DOR LMC簇报告的恒星形成。
Westerlund 1 (Wd 1) is one of the most relevant star clusters in the Milky Way to study massive star formation, although it is still poorly known. Here, we used photometric and spectroscopic data to model the eclipsing binary W36, showing that its spectral type is O6.5 III + O9.5 IV, hotter and more luminous than thought before. Its distance $d_{\rm W36}$ $=$ 4.03$\pm$0.25 kpc agrees, within the errors, with three recent Gaia-EDR3-based distances reported in Paper I, Beasor & Davies, and by Negueruela's group. However, they follow different approaches to fix the zero-points for red sources such as those in Wd 1 and to select the best approach, we used an accurate modelling of W36. The weighted mean distance of our parallax (Paper I) and binary distances results in $d_{\rm wd1}$ = 4.05 $\pm$0.20 kpc, with an unprecedented accuracy of 5%. We adopted isochrones based on the Geneva code with supersolar abundances to infer the age of W36B as 6.4 $\pm$ 0.7 Myr. This object seems to be part of the prolific star formation burst represented by OB giants and supergiants that occurred at 7.1 $\pm$ 0.5 Myr ago, which coincides with the recently published PMS isochrone with age 7.2 Myr. Other BA-type luminous evolved stars and Yellow Hypergiants spread in the age range of 8--11 Myr. The four Red Supergiants discussed in paper I represent the oldest population of the cluster with an age of 10.7 $\pm$ 1 Myr. The multiple episodes of star formation in Wd 1 are reminiscent of that reported for the R136/30 Dor LMC cluster.
