AI 中文总结
本研究利用盖亚DR2数据对四个最显著恒星环进行运动学与光度分析，发现它们并非物理相关的年轻恒星群，而是视线投影效应，并验证了现有数据可高显著性分析此类结构。
AI 中文摘要
大约50年前，Isserstedt（1968）发现了1000个环状结构（称为恒星环）。它们被认为是壳状触发恒星形成产生的年轻恒星群，这将使它们成为例如旋臂的极佳示踪体。这些结构被忽视了40年，我们利用高精度的运动学、天体测量和光度数据来研究四个最显著的恒星环。目的是调查这些结构是否确实是物理上相关的恒星群。我们使用了盖亚DR2的自行和视差来计算距离并寻找共同属性。研究了使用BVJHKs测量绘制的颜色-星等图，并拟合了等时线。四个恒星环中没有一个由物理上相关的年轻恒星群组成。视线方向上恒星的位置在天空中模拟了环状结构。颜色-星等图是典型的综合场星族特征，而非例如年轻星团的特征。目前可用的数据足以以高统计显著性分析环状结构。这允许在银河系中重新搜索此类结构。
英文摘要
About 50 years ago, one thousand ring-like structures (called stellar-rings) were discovered by Isserstedt (1968). They were believed to be groups of young stars formed by shell-like triggered star formation, which would make them excellent tracers of spiral arms, for example. Neglected for 40 years, we used highly accurate kinematic, astrometric, and photometric data to investigate the four most prominent stellar rings. The aim is to investigate if those structures are indeed physically related groups of stars. We used proper motions and parallaxes from the Gaia DR2 to calculate distances and to search for common properties. Color-magnitude diagrams using BVJHKs measurements were investigated and isochrones fitted. None of the four stellar rings consists of a physically related group of young stars. The location of stars in the line-of-sight mimics a ring-like structure on the sky. The color-magnitude diagrams are typical for an integrated field population and not for a young star cluster, for example. The currently available data are sufficient to analyze ring-like structures with a high statistical significance. This allows a new search for such structures in the Milky Way.
Comments9 pages, 6 figures, Astronomische Nachrichten, 2018, Volume 339, Issue 672, pp. 672-679
