Collaborative Research: The Evolution of Magnetic Complexity in Old Sun-like Stars

合作研究：老类太阳恒星的磁复杂性演化

• 批准号: 2205888
• 负责人: Jennifer van Saders
• 金额: $ 44.48万
• 依托单位: University of Hawaii
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2022
• 资助国家: 美国
• 起止时间: 2022-09-01 至 2025-08-31
• 项目状态: 未结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2205888&HistoricalAwards=false
• 关键词: Collaborative; Research; Evolution; Magnetic; Complexity

Principal Investigators Metcalfe and van Saders will take polarized spectra of a sample of stars to assess the strength and complexity of their magnetic fields. For stars like our Sun, the stellar wind slowly escapes along the star’s magnetic field lines and slows down the rate at which the star rotates over a period of billions of years. This process is called magnetic braking. Slowing rotation leads to a mid-life crisis and the magnetic field generation starts to fail. Stars switch from periods of activity (strong magnetic field with many flares, sunspots, and outbursts) to in-activity (weaker more complex magnetic field with reduced activity). Determining when and how these switches occur will improve our understanding of how stars age. To broaden participation the team plan to lead a 15-week "Survival Skills for Scientists" seminar at the University of Colorado and a summer Research Experience for Teachers at the University of Hawaii.The team will observe 12 stars using the Potsdam Echelle Polarimetric and Spectroscopic Instrument (PEPSI) at the Large Binocular Telescope combined with contemporaneous spectra using Las Cumbres Observatory's Network of Robotic Echelle Spectrographs (NRES) to determine the level of activity. Follow-up detailed magnetic field maps will be obtained using the Echelle SpectroPolarimetric Device for the Observation of Stars (ESPaDOnS) on the Canada-France-Hawaii Telescope (CFHT). The resulting constraints on how the properties of stellar magnetism depend on rotation and mass beyond middle-age will have implications for theoretical models of angular momentum loss from magnetized stellar winds, the use of gyrochronology as a technique for inferring stellar ages, and will inform predictions of long term "space weather" for the Sun and other planetary systems.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.

首席研究员梅特卡夫和范萨德斯将采集恒星样本的偏振光谱来评估其磁场的强度和复杂性，对于像太阳这样的恒星，恒星风会沿着恒星的磁场线缓慢逃逸，并减慢逃逸的速度。恒星旋转的时间长达数十亿年，旋转速度减慢会导致中年危机，恒星的磁场产生开始从活动期（有许多耀斑的强磁场）转变。确定这些转变发生的时间和方式将提高我们对恒星如何衰老的理解，该团队计划领导为期 15 周的“生存”活动。科罗拉多大学的“科学家技能”研讨会和夏威夷大学的教师夏季研究体验。该团队将使用波茨坦阶梯状偏振和光谱仪器观测 12 颗恒星（PEPSI）在大型双目望远镜上结合使用拉斯昆布雷斯天文台的机器人阶梯光谱仪网络（NRES）的同期光谱来确定后续详细的磁场图，并将使用阶梯光谱偏振设备进行观测。加拿大-法国-夏威夷望远镜（CFHT）上的恒星（ESPaDOnS）由此产生的对恒星属性的限制。中年之后磁性依赖于旋转和质量，这将对磁化恒星风的角动量损失的理论模型、陀螺年代学作为推断恒星年龄的技术的使用产生影响，并将为长期“太空天气”的预测提供信息。太阳和其他行星系统。该奖项反映了 NSF 的法定使命，并通过使用基金会的智力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

Constraints on Magnetic Braking from the G8 Dwarf Stars 61 UMa and τ Cet

G8 矮星 61 UMa 和 Ï Cet 对磁制动的约束

• DOI: 10.3847/2041-8213/acce38
• 发表时间: 2023-04
• 期刊: The Astrophysical Journal Letters
• 作者: Metcalfe, Travis S.;Strassmeier, Klaus G.;Ilyin, Ilya V.;van Saders, Jennifer L.;Ayres, Thomas R.;Finley, Adam J.;Kochukhov, Oleg;Petit, Pascal;See, Victor;Stassun, Keivan G.;et al
• 通讯作者: et al