Magnetic Evolution of Sun-like Activity Cycles

类太阳活动周期的磁演化

• 批准号: 1812634
• 负责人: Travis Metcalfe
• 金额: $ 22.55万
• 依托单位: SPACE SCIENCE INSTITUTE
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2018
• 资助国家: 美国
• 起止时间: 2018-09-01 至 2021-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1812634&HistoricalAwards=false
• 关键词: Magnetic; Evolution; Sun; like; Activity

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.

太阳的磁场活动在大约11年的周期内变强变弱，调节地球所经历的辐射和带电粒子环境，称为“空间天气”。“几十年的观测表明，其他恒星也显示出有规律的活动周期。 太阳活动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一研究方案将为了解太阳和恒星的活动周期如何在其一生中发生变化奠定观测基础，包括与行星可居住性的可能联系。这些发展还将提供有关磁发电机的基本物理学的见解，磁发电机在类太阳恒星内部，在异国情调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对青年科学家进行天文数据处理和观测时间序列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、分析和解释两&个已知自转速率的恒星样本中恒星活动的新的时间序列光谱Ca II H K（Ca HK）观测结果，旨在探测太阳的前体和同时代的太阳。对于来自威尔逊山调查的旋转速度比太阳快的年轻太阳类似物的样本，该项目将在几年内获得预定的Ca HK观测，以寻找相对较短的活动周期，这些周期似乎是11年太阳周期的前兆。第二个样本将集中在较暗的恒星上，这些恒星的星震特性和旋转速率已经从美国宇航局的开普勒使命中确定，包括具有一系列跨越中年磁性转变的进化状态的目标。该项目将获得预定的Ca HK对该样本的观测结果，以确定过渡的开始和持续时间，并在全球发电机关闭时限制各个阶段恒星活动的变化。所有的观测数据都将通过Las Cumbres天文台全球望远镜网络获得。该奖项反映了NSF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。

项目成果

LBT/PEPSI Spectropolarimetry of a Magnetic Morphology Shift in Old Solar-type Stars

老太阳型恒星磁形态转变的 LBT/PEPSI 分光偏振法

• DOI: 10.3847/2041-8213/ab5e48
• 发表时间: 2019
• 期刊: The Astrophysical Journal
• 作者: Metcalfe, T. S.;Kochukhov, O.;Ilyin, I. V.;Strassmeier, K. G.;Godoy-Rivera, D.;Pinsonneault, M. H.
• 通讯作者: Pinsonneault, M. H.

The Evolution of Rotation and Magnetic Activity in 94 Aqr Aa from Asteroseismology with TESS

• DOI: 10.3847/1538-4357/aba963
• 发表时间: 2020-07
• 期刊: The Astrophysical Journal
• 作者: T. Metcalfe;J. V. van Saders;S. Basu;D. Buzasi;W. Chaplin;R. Egeland;R. García;P. Gaulme;D. Hub

An X-ray activity cycle on the young solar-like star ɛ Eridani

年轻的类太阳恒星 Eridani 的 X 射线活动周期

• DOI: 10.1051/0004-6361/201936479
• 发表时间: 2020
• 期刊: Astronomy & Astrophysics
• 影响因子: 6.5
• 作者: Coffaro, M.;Stelzer, B.;Orlando, S.;Hall, J.;Metcalfe, T. S.;Wolter, U.;Mittag, M.;Sanz-Forcada, J.;Schneider, P. C.;Ducci, L.
• 通讯作者: Ducci, L.