A New Spin on M Dwarf Ages and Evolution

体积小、温度相对较低、质量不到太阳一半的恒星被称为M矮星（或红矮星）。它们是银河系中最常见的恒星类型。M矮星寿命很长，被认为是银河系中化学元素分布的可靠示踪剂。它们也是已知最多产的行星宿主，尤其是在“宜居带”轨道上运行的地球大小的行星。夏威夷大学马诺阿分校（University of hawaii at Manoa）的一个研究小组将结合新的天文观测结果、基于太空的恒星调查结果和恒星旋转的计算机模型来确定它们的年龄。M矮星的准确年龄将允许追踪星系中元素的分布，并将追踪银河系历史上的行星环境。此外，这项研究将有助于更好地理解年轻M矮星的快速旋转和强磁活动，这将改进它们在许多波长上发射光的模型，这是任何围绕它们运行的行星环境的重要因素。研究人员将把该项目的各个方面整合到夏威夷大学马诺阿分校的一个年度项目中，该项目培训和指导一批人口统计学上不同的高中生，以增强他们对科学、技术、工程和数学（STEM）学科的信心和理解，并激发他们对STEM相关职业的兴趣。学生们将与一名研究人员合作，根据莫纳克亚山望远镜获得的数据开展一个项目，并在完成项目期间接受为期6个月的持续指导。该研究计划旨在开发一种基于M矮星旋转的计时器，并研究M矮星旋转、多样性、盘和前主序演化之间的联系。它将利用新的观测结果、天基调查结果和恒星旋转模型：(1)在两个太阳年龄的星团（M67和Ruprecht 147）中建立M矮星的旋转序列（陀螺仪），作为自旋下降模型的关键校准点；(2)为Hyades制作质量旋转图，这是M矮星自旋下降模型的关键中间基准，该模型对双星进行了统一和更彻底的审查；(3)证实或反驳绘人座Beta移动群中伴星与主序前M矮星旋转之间的相关性，作为盘锁定场景的测试；(4)测量所选M矮双星中各组分的质量、半径、亮度和磁场，量化旋转和磁场活动对主序前演化的影响。该奖项反映了美国国家科学基金会的法定使命，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。

Small, relatively cool stars, less than half the mass of the Sun, are called M dwarf (or red dwarf) stars. These are the most common type of star in the Milky Way. M dwarfs are long-lived, and known to be reliable tracers of the distribution of chemical elements in the Galaxy. They are also the most prolific known hosts of planets, particularly Earth-size planets orbiting in the "habitable zone". A research team at the University of Hawai'i at Manoa will use a combination of new astronomical observations, results from space-based surveys of stars, and computer models of stellar rotation to determine their ages. Accurate ages of M dwarfs will permit tracing distribution of the elements in the Galaxy and will track the planetary environments over Galactic history. Moreover, this research will lead to a better understanding of the rapid rotation and strong magnetic activity of young M dwarfs, which will improve models of their emission of light at many wavelengths, important factors for the environment of any planets that orbit them. The investigators will integrate aspects of this project into an annual program at the University of Hawai'i at Manoa that trains and mentors cohorts of demographically diverse high school students to boost their confidence and understanding of Science, Technology, Engineering, and Mathematics (STEM) subjects and stimulate their interest in STEM-related careers. The students will work with an investigator on a project based on data obtained at a telescope on Mauna Kea and receive ongoing mentoring for six months while they complete their project.The research program seeks to develop a chronometer based on the rotation of M dwarf stars and to study the connections between M dwarf rotation, multiplicity, disks, and pre-main sequence evolution. It will use new observations, results from space-based surveys, and models of stellar rotation to (1) establish a rotational sequence (gyrochrone) of M dwarfs in two solar-aged clusters (M67 and Ruprecht 147) as critical calibration points for spin-down models; (2) produce a mass-rotation diagram for the Hyades, a key intermediate bench-mark for M dwarf spin-down models, which is uniformly and more thoroughly vetted for binaries; (3) confirm or refute a correlation between stellar companions and rotation among pre-main sequence M dwarfs in the Beta Pictoris Moving Group as a test of the disk-locking scenario; and (4) measure masses, radii, luminosities, and magnetic fields of components in selected M dwarf binaries to quantify the effect of rotation and magnetic activity on pre-main sequence evolution.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.