This topical issue of Astronomische Nachrichten/Astronomical Notes contains a cross section of the articles that were presented at the 16th Potsdam Thinkshop, which was organized by the Leibniz Institute for Astrophysics Potsdam (AIP) and held on its campus in Babelsberg in September 2019. The title of the Thinkshop was “The rotation periods of cool stars: Measurements, uses, connections and prospects.”

The motivations for organizing this Thinkshop were manifold. Rotation periods are rapidly becoming available for large numbers of cool stars, both from ground‐based efforts and from space missions such as Kepler, Gaia, TESS, and—before long—PLATO. These rotation periods offer independent and complementary information about stars in comparison to prior techniques. For instance, they are often used to derive ages for cool stars via a procedure known as gyrochronology. Rotation also helps to interpret and illuminate various magnetic and activity behaviors of stars, and rotation in turn is likely itself affected by various internal and external factors. Related topics include open clusters, membership verification, metallicity dependence, binary stars, effects of close companions, and various others, which might be relevant to the aims of well‐reasoned measurement, usage, and interpretation of rotation periods and to the future prospects of gyrochronology. The workshop enabled researchers to present their results in a more intimate setting than often possible, and significant time was reserved for discussions and interaction.

The Scientific Organizing Committee consisted of Sydney Barnes (AIP, chair), Constantine Deliyannis (Indiana University, United States), Elisa Distefano (INAF, Catania, Italy), Jose D. do Nascimento (DFTE‐UFRN, Brazil & CfA‐SAO, United States), Thomas Granzer (AIP), Silva Järvinen (AIP), Elisabeth Newton (Dartmouth College, United States), Steven Saar (CfA, United States), and Klaus Strassmeier (AIP). A total of 54 participants from a number of different continents attended the Thinkshop. Further information is available on the Internet at: https://thinkshop.aip.de/16/cms/.

All of the relevant topics listed above were mentioned in some form or the other during the Thinkshop, and many were discussed extensively. We are pleased to include a selection of the presented articles in this Special Issue. All contributions to this issue were reviewed by expert referees.

We would like to express our gratitude to the Leibniz Institute for Astrophysics Potsdam for hosting this conference and to the AIP administrative staff for their competent administrative support.

本期《天文学杂志》 /《天文学笔记》包含在第16届波茨坦思想店上发表的文章的横断面，该书店由波布坦的莱布尼兹天体物理研究所（AIP）组织，于2019年9月在其位于Babelsberg的校园举行。 Thinkshop的标题是“凉爽恒星的自转周期：测量，用途，联系和前景”。

组织此Thinkshop的动机是多种多样的。从地面努力以及开普勒，盖亚，TESS等太空飞行任务以及后来的PLATO等太空飞行任务以来，大量酷星的自转周期迅速变得可用。与现有技术相比，这些自转周期提供有关恒星的独立且互补的信息。例如，它们经常被用来通过一个称为年代学的程序推算出凉爽恒星的年龄。旋转还有助于解释和阐明恒星的各种磁性和活动行为，而旋转本身本身又可能受到各种内部和外部因素的影响。相关主题包括开放星团，成员资格验证，金属性依赖性，双星，密友的影响以及其他各种因素，这可能与合理测量，使用和解释旋转周期的目的以及陀螺年代学的未来前景有关。讲习班使研究人员能够以比通常情况下更亲密的方式展示其结果，并为讨论和互动留出了大量时间。

科学组委会由悉尼巴恩斯（AIP，主席），君士坦丁·德利安尼斯（康斯坦丁·德莱尼尼斯）（美国印第安纳大学），伊丽莎·迪斯泰法诺（Elisa Distefano）（意大利卡塔尼亚（INAF）的意大利），何塞·多纳西门托（DFTE‐UFRN，巴西和CfA‐SAO，美国），托马斯·格兰泽（AIP），席尔瓦·耶尔文（AIP），伊丽莎白·牛顿（美国达特茅斯学院），史蒂文·萨尔（美国CfA）和克劳斯·斯特拉斯迈尔（AIP）。来自不同大洲的总共54位参与者参加了Thinkshop。有关更多信息，请访问Internet：https：//thinkshop.aip.de/16/cms/。

上面列出的所有相关主题在Thinkshop中都以某种形式或其他形式提及，其中许多主题进行了广泛讨论。我们很高兴在本期特刊中提供一些精选的文章。对这个问题的所有贡献均经过专家裁判的审查。

我们要感谢莱布尼兹波茨坦天体物理学研究所主办本次会议，并感谢AIP行政人员的出色行政支持。