论文标题
开放式集群：时间尺度，核心崩溃和蓝色散落者
Open clusters: time-scales, core collapse and blue stragglers
论文作者
论文摘要
我们开发了一个数学模型来得出时间尺度和BS恒星的存在。该模型基于质量通过一个圆的变化到一个半径定义的群集中；该质量交叉被翻译成一个微分方程，可以在给定半径（R）和确定的时间（t）中整合它。从这个方程式中，我们可以得出不同的时间尺度，使我们得出的结论是：不包含蓝色斗争者（BS）恒星的群集比包含BS的簇年轻。在包含BS恒星的簇中，占群集质量一半的体积比与没有BS星的簇相对应的群集质量要大，但是赶上它的时间较短。我们还通过这个方程式研究了群集的恒星和该浓度停止/保留的区域的核心崩溃。通过关系$ c/ch $确定此区域，为$ c = \ log（rt/rc）$和$ ch = \ log（rc/rh）$。其中RT和RC分别是潮汐和核心半径，RH是半径，其中一半的簇质量是浓缩的。该模型还驱使我们得出这样的结论：集群中的蓝色Straggler恒星数量遵循分布函数，其组件是放松时间和年龄之间的比例，标记为$ \ it f $，而一个因子，名为$ \ varpi $，这是BS的来源的指示。 $ \ varpi $随着BS数量的增加而增加，但仅限于$ \ sim $ 5.0。提到的分布功能表示为$ \ it nbs $ $ \ sim $ $ \ it f^3 $（$ \ frac {1} {e^{\ frac {f} {f} {\ varpi}}} - 1} $）。该功能的有效性是通过将观察到的蓝色Straggler（BS）恒星数量与可用OC样本中预测的恒星数量相匹配的。
We developed a mathematical model to derive time scales and the presence of BS stars. The model is based on the variation of mass through a circle into the cluster defined by a radius, and at a time; this mass cross is translated into a differential equation that it can be integrated for a given radius (r) and a determined time (t). From this equation we can derive the different time scales that allows us to reach conclusions like: clusters not containing blue strugglers (BS) stars disappear younger than those clusters containing BS. In clusters containing BS stars, the volume which takes up half of the cluster mass is bigger than the one corresponding to clusters without BS stars but the time to catch it up is shorter. We also studied, by means of this equation, the core collapse of stars of the cluster and the region where this concentration is stopped/retained; this region is identified by means of the relation $c/ch$, being $c=\log(rt/rc)$ and $ch=\log(rc/rh)$. Where rt and rc are the tidal and the core radius respectively, and rh is the radius where half of the cluster mass is concentrated. The model also drove us to the conclusion that the number of the blue straggler stars in a cluster follows a distribution function whose components are the ratio between relaxation time and the age, labelled as $\it f$, and a factor, named $\varpi$, which is an indicator of the origin of the BS; $\varpi$ increases as the number of BS increase but it is limited to$\sim$5.0. The mentioned distribution function is expressed as $\it NBS$ $\sim$ $\it f^3$($\frac{1}{e^{\frac{f}{\varpi}}-1}$). The validity of this function was carried out by means of matching the number of observed blue straggler (BS) stars to the number of predicted ones in the available sample of OC.
