论文标题
宽阔的二进制组很少见
Wide binaries are rare in open clusters
论文作者
论文摘要
二进制恒星的种群统计是恒星形成模型的重要输出。然而，由于系统的出生环境中的相互作用以及范围范围的层次三重系统的展开，广泛的二进制组的种群随着时间的流逝而发展。因此，在恒星形成区域或OB关联中观察到的广泛的二元种群可能无法准确反映出最终将最终到达现场的广泛二元种群。我们使用GAIA DR2数据选择三个开放簇的成员Alpha〜Per，Pleiades和praesepe，并标记由于过度肿瘤性或升高的星体噪声而可能无法解决的二进制成员。然后，我们确定每个群集中解决的较广泛的二元种群，将其与无关集群成员的一致配对分开。 We find that these clusters have an average wide binary fraction in the 300-3000\,AU projected separation range of 2.1$\pm^{0.4}_{0.2}$\% increasing to 3.0$\pm^{0.8}_{0.7}$\% for primaries with masses in the 0.5-1.5\,$M_{\odot}$ range.这显着低于观察到的范围二元分数，但在这些动态处理的环境中显示了一些广泛的二进制组。我们将结果与另一个开放式群集（hyades）和两个可能起源于宽松的联想（年轻移动组和双鱼座 - 厄里达努斯流）的年轻恒星种群进行了比较。我们发现，羟基的二进制文件的赤字也很大，而松散关联的产物在野外水平或更高的二元分数中。
The population statistics of binary stars are an important output of star formation models. However populations of wide binaries evolve over time due to interactions within a system's birth environment and the unfolding of wide, hierarchical triple systems. Hence the wide binary populations observed in star forming regions or OB associations may not accurately reflect the wide binary populations that will eventually reach the field. We use Gaia DR2 data to select members of three open clusters, Alpha~Per, the Pleiades and Praesepe and to flag cluster members that are likely unresolved binaries due to overluminosity or elevated astrometric noise. We then identify the resolved wide binary population in each cluster, separating it from coincident pairings of unrelated cluster members. We find that these clusters have an average wide binary fraction in the 300-3000\,AU projected separation range of 2.1$\pm^{0.4}_{0.2}$\% increasing to 3.0$\pm^{0.8}_{0.7}$\% for primaries with masses in the 0.5-1.5\,$M_{\odot}$ range. This is significantly below the observed field wide binary fraction, but shows some wide binaries survive in these dynamically highly processed environments. We compare our results with another open cluster (the Hyades) and two populations of young stars that likely originated in looser associations (Young Moving Groups and the Pisces-Eridanus stream). We find that the Hyades also has a deficit of wide binaries while the products of looser associations have wide binary fractions at or above field level.
