Magnetic Evolution of Sun-like Activity Cycles

太阳的磁场活动在大约11年的周期中变得更强和更弱，调节着地球所经历的辐射和带电粒子环境，即“太空天气”。几十年的观测显示，其他恒星也有规律的活动周期。太阳周期似乎是一个异常值，这可能意味着太阳正处于一个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计划将建立一个观测基础，以了解活动周期如何在太阳和恒星的生命周期中变化，包括与行星宜居性的可能联系。这些进展还将提供有关磁发电机的基本物理学的见解，这种发电机在类太阳恒星内部、奇异的天体物理环境和实验室等离子体中运行。通过暑期学生参与研究，研究活动将直接有助于培训青年科学家掌握天文数据处理和观测时间序列分析的技术。首席研究员还将继续他的获奖每月科学专栏《实验室笔记》，将最近的科学发现与当地科学家和他们工作的实验室的活动联系起来。研究人员将获得、分析和解释两个已知自转速度的恒星样本中恒星活动的新的时间序列光谱Ca II H&amp；K(CaHK)观测，旨在探测太阳的前兆和同时代。对于威尔逊山调查中的一个比太阳自转更快的年轻太阳类似物样本，该项目将在几年内获得排队排定的CaHK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。第二个样本将聚焦于具有星震特性和自转速度的较暗恒星，这些恒星已经由NASA的开普勒任务确定，包括具有一系列演化状态的目标，这些状态跨越了中年的磁性转变。该项目将获得这一样本的排队计划的Ca HK观测，以表征过渡的开始和持续时间，并在全球发电机关闭的不同阶段限制恒星活动的可变性。所有的观测结果都将通过拉斯坎布雷天文台的全球望远镜网络获得。这一奖项反映了NSF的法定使命，并通过使用基金会的智力优势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.