Magnetic Evolution of Sun-like Activity Cycles

太阳的磁场活动在大约11年的周期内变得越来越强和越来越弱，从而调节了地球所经历的辐射和带电粒子环境，即“太空天气”。几十年的观测表明，其他恒星也表现出规律的活动周期。太阳周期似乎是一个异常值，这可能意味着太阳正处于所有中年恒星都会发生的过渡阶段。空间科学研究所的这项研究项目将为了解太阳和恒星的生命周期中活动周期的变化建立一个观测基础，包括与行星可居住性的可能联系。这些进展还将提供关于磁发电机的基本物理的见解，磁发电机在类太阳恒星内部、在奇异的天体物理环境中以及在实验室等离子体中运行。这些研究活动将通过暑期学生参与研究，直接促进青年科学家在天文数据处理和时间序列观测分析技术方面的培训。首席研究员还将继续他为科罗拉多州博尔德周报撰写的获奖月度科学专栏“实验室笔记”，将最近的科学发现与当地科学家及其工作的实验室的活动联系起来。研究人员将获得，分析和解释新的时间序列光谱Ca II H &amp； K （Ca HK）观测到的两个已知旋转速率的恒星样本的恒星活动，旨在探测太阳的前身和同时代的恒星。对于威尔逊山调查的年轻太阳类似物样本，其旋转速度比太阳快，该项目将在数年内获得排队安排的Ca - HK观测，以寻找相对较短的活动周期，这些活动周期似乎是11年太阳周期的前兆。第二个样本将集中在具有星震特性和旋转速度的较暗的恒星上，这些恒星已经由美国宇航局的开普勒任务确定，包括具有一系列跨越中年磁转变的进化状态的目标。该项目将获得该样本的排队调度的Ca - HK观测结果，以表征转变的开始和持续时间，并对全球发电机关闭时不同阶段恒星活动的可变性进行限制。所有的观测结果都将通过拉斯康布雷斯天文台的全球望远镜网络获得。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

The magnetic activity of the Sun becomes stronger and weaker over roughly an 11-year cycle, modulating the radiation and charged particle environment experienced by the Earth as "space weather." Decades of observations have revealed that other stars also show regular activity cycles. The solar cycle appears to be an outlier, which may mean that the Sun is in a transitional phase that occurs in all middle-aged stars. This research program at the Space Science Institute will establish an observational foundation for understanding how activity cycles change over the lifetimes of the Sun and stars, including possible connections to planetary habitability. These developments will also provide insight about the fundamental physics of magnetic dynamos, which operate inside Sun-like stars, in exotic astrophysical environments, and in laboratory plasmas. The research activities will directly contribute to the training of young scientists in the techniques of astronomical data processing and analysis of time series of observations, through the participation of summer students in the research. The principal investigator will also continue his award-winning monthly science column "Lab Notes" for the Boulder, CO weekly newspaper, connecting recent science discoveries with the activities of local scientists and the laboratories where they work.The researchers will obtain, analyze, and interpret new time-series spectroscopic Ca II H & K (Ca HK) observations of stellar activity in two samples of stars with known rotation rates, designed to probe both the precursors and the contemporaries of the Sun. For a sample of young solar analogs from the Mount Wilson survey that rotate faster than the Sun, the project will obtain queue-scheduled Ca HK observations over several years to search for the relatively short activity cycles that appear to be the precursors of the 11-year solar cycle. The second sample will focus on fainter stars with asteroseismic properties and rotation rates already determined from NASA's Kepler mission, including targets with a range of evolutionary states that span the middle-age magnetic transition. The project will obtain queue-scheduled Ca HK observations of this sample to characterize the onset and duration of the transition, and to place limits on the variability of stellar activity at various stages as the global dynamo shuts down. All of the observations will be obtained using the Las Cumbres Observatory global telescope network.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.