Stellar and Solar Magnetic Activity Cycles

恒星和太阳磁活动周期

• 批准号: 0742144
• 负责人: Jeffrey Hall
• 金额: $ 47.92万
• 依托单位: Lowell Observatory
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2008
• 资助国家: 美国
• 起止时间: 2008-01-15 至 2011-09-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0742144&HistoricalAwards=false
• 关键词: Stellar; Solar; Magnetic; Activity; Cycles

This effort extends the Lowell Observatory Solar-Stellar Spectrograph (SSS) project, which has operated continuously since 1994. The SSS is a dual echelle spectrograph used for unique, long-term, synoptic observations of the Sun and Sun-like stars. In this project, the Principal Investigator (PI) will obtain observations of the Ca II H and K solar emission lines during the minimum of solar cycle 23/24, as well as make similar measurements for about 40 'solar analog' stars. These Ca II emission lines serve as proxies for solar and stellar chromospheric activity and can be used to study cyclical behavior. Secular trends in solar luminosity are best identified at cycle minima, and are critical for understanding long-term solar luminosity variations. These solar observations will allow the PI's team to make detailed comparison of emissions at successive solar minima, for comparisons with ongoing total solar irradiance (TSI) measurements. For stars, such Ca II observations have provided direct observational evidence for stellar activity cycles, rotational modulation, and differential rotation. The PI's team has identified a set of about 40 'solar analog' stars that may provide critical clues regarding the behavior of stellar activity and luminosity. Studying these stars could provide insight into the Sun's past and future. By better characterizing the evolution of solar luminosity and that of the Sun's nearest stellar analogs, these observations may provide astrophysical insight into long-term solar activity and luminosity variations, and may also be useful for determining the likely level of solar influences on terrestrial climate change.The PI's team will train Northern Arizona University students in solar and stellar observing and astronomical data analysis. The project will also involve a high school student in complementary observations of active binary stars as part of an accelerated research program operated by his school district. The PI will continue to disseminate his results online for broad public access, education, and participation. The PI's team will remain active in public outreach by offering presentations of their results throughout Arizona and the Southwest.

这一努力扩展了自1994年以来一直持续运作的洛厄尔天文台太阳-恒星光谱仪（SSS）项目。SSS是一台双阶梯光栅摄谱仪，用于对太阳和类太阳恒星进行独特的、长期的天气观测。在这个项目中，主要研究者将在太阳活动周期23/24的最小期获得Ca II H和K太阳发射线的观测结果，并对大约40颗“太阳模拟”恒星进行类似的测量。这些钙II发射线作为太阳和恒星色球活动的代理，可用于研究周期性行为。太阳光度的长期趋势最好在周期最小值时确定，并且对于理解长期的太阳光度变化至关重要。这些太阳观测将使PI的团队能够详细比较连续太阳极小期的排放量，以便与正在进行的太阳总辐照度（TSI）测量进行比较。对于恒星来说，这种Ca II观测为恒星活动周期、自转调制和差异自转提供了直接的观测证据。PI的团队已经确定了一组大约40颗“太阳模拟”恒星，它们可能提供有关恒星活动和光度行为的关键线索。研究这些恒星可以提供对太阳过去和未来的洞察力。通过更好地描述太阳光度和太阳最近的恒星类似物的演变，这些观测可能为长期太阳活动和光度变化提供天体物理学见解，也可能有助于确定太阳对地球气候变化的可能影响程度。PI的团队将培训北方亚利桑那大学的学生进行太阳和恒星观测以及天文数据分析。该项目还将涉及一名高中生对活跃双星的补充观测，作为其学区实施的加速研究计划的一部分。PI将继续在网上传播他的结果，以广泛的公众访问，教育和参与。PI的团队将通过在亚利桑那州和西南部提供他们的结果介绍，继续积极参与公共宣传。