Rotation and magnetic activity are intimately linked in main-sequence stars of G or later spectral types. The presence and level of magnetic activity depend on stellar rotation, and rotation itself is strongly influenced by strength and topology of the magnetic fields. Open clusters represent especially useful targets to investigate the rotation/activity/age connection. The open cluster M11 has been studied as a part of the RACE-OC project (Rotation and ACtivity Evolution in Open Clusters), which is aimed at exploring the evolution of rotation and magnetic activity in the late-type members of open clusters with different ages. Photometric observations of the open cluster M11 were carried out in June 2004 using LOAO 1m telescope. The rotation periods of the cluster members are determined by Fourier analysis of photometric data time series. We further investigated the relations between the surface activity, characterized by the light curve amplitude, and rotation. We have discovered a total of 75 periodic variables in the M11 FoV, of which 38 are candidate cluster members. Specifically, among cluster members we discovered 6 early-type, 2 eclipsing binaries and 30 bona-fide single periodic late-type variables. Considering the rotation periods of 16 G-type members of the almost coeval 200-Myr M34 cluster, we could determine the rotation period distribution from a more numerous sample of 46 single G stars at an age of about 200-230 Myr and determine a median rotation period P=4.8d. A comparison with the younger M35 cluster (~150 Myr) and with the older M37 cluster (~550 Myr) shows that G stars rotate slower than younger M35 stars and faster than older M37 stars. The measured variation of the median rotation period is consistent with the scenario of rotational braking of main-sequence spotted stars as they age.
The VVV Templates Project. Towards an Automated Classification of VVV Light-Curves. I. Building a database of stellar variability in the near-infrared
上下文维斯塔变星（英语：Vista Variables in the Vía Láctea）是欧洲南方天文台（ESO）于2010年在可见光和红外巡天望远镜（VISTA）上进行的一项观测，观测对象是银河系的核球和邻近的盘面。VVV最终将提供一个深近红外地图集，其中包括五个通带（ZYJHK_S）的光度和位置，以及一个100万至1000万个可变点源的目录-大多数是未知的-需要分类。目的。我们在这项工作中介绍的VVV模板项目的主要目标是开发和测试用于VVV光变曲线自动分类的机器学习算法。由于VVV是第一个大规模的，多历元的调查恒星的变化在近红外，模板光变曲线所需的训练分类算法是不可用的。在该系列的第一篇论文中，我们描述了红外恒星变化的综合数据库的建设。方法.首先，我们在文献和公共数据档案中进行了系统的搜索，第二，我们协调了一个全球性的观测活动，第三，我们利用VVV变率数据库本身（光学）知名的恒星收集高质量的红外线-数百颗变星的曲线。结果我们现在已经收集了大量的（而且还在增加）红外模板光变曲线。该数据库将用作机器学习算法的训练集，该算法将自动对VVV产生的光变曲线进行分类。这一自动分类的结果将在即将发表的系列论文中介绍。
The ZTF Source Classification Project: II. Periodicity and variability processing metrics
目前这一代的全天巡天正在迅速扩大我们研究可变和瞬态源的能力。这些调查，具有各种灵敏度，节奏和视野，探测许多时间尺度和震级范围。来自Zwicky瞬态设施（ZTF）的数据提供了一个机会，可以找到从几分钟到几个月的时间尺度上的变量。在本文中，我们提出的代码库，ztfperiodic，和计算指标采用的目录的基础上ZTF的第二次数据发布。我们描述了公开可用的，图形处理单元优化的周期发现算法，并强调现有的和未来的图形处理单元集群的好处。我们展示了如何生成指标作为输入到这个规模的目录是可能的未来ZTF数据发布。未来还需要进一步的工作来获得来自Vera C. Rubin Observatory's Legacy Survey of Space and Time的相关文章
