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，以评估其磁场的强度和复杂性。对于像我们的太阳这样的恒星，恒星风沿着恒星的磁力线缓慢地逃逸，并减缓了恒星在数十亿年的周期内旋转的速度。这一过程称为磁制动。缓慢的自转会导致中年危机，磁场产生开始失效。恒星从活动期(强磁场，有许多耀斑、太阳黑子和爆发)转换到非活动期(较弱的复杂磁场，活动减少)。确定这些变化发生的时间和方式将有助于我们更好地理解恒星的年龄。为了扩大参与，该团队计划在科罗拉多大学领导一个为期15周的“科学家的生存技能”研讨会，并在夏威夷大学为教师进行夏季研究体验。该团队将使用大型双筒望远镜上的波茨坦Echelle偏振和光谱仪器(Pepsi)观察12颗恒星，并使用拉斯卡布雷斯天文台的机器人Echelle光谱仪网络(NRES)观察同期光谱，以确定活动水平。后续的详细磁场图将使用加拿大-法国-夏威夷望远镜(CFHT)上用于观测恒星(Espadons)的Echelle光谱偏振装置获得。由此产生的对中年后恒星磁性如何依赖于自转和质量的限制，将对磁化恒星风的角动量损失理论模型产生影响，将回转年代学用作推断恒星年龄的技术，并将为太阳和其他行星系统的长期“空间天气”预测提供信息。该奖项反映了美国国家科学基金会的法定任务，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。

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
• 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.
• 通讯作者: Stassun, Keivan G.