A New Spin on M Dwarf Ages and Evolution

质量不到太阳一半的相对较冷的小恒星被称为M矮星(或红矮星)。这些是银河系中最常见的恒星类型。M矮星寿命很长，是银河系中化学元素分布的可靠示踪者。它们也是已知最多的行星宿主，特别是在“可居住带”轨道上运行的地球大小的行星。夏威夷大学马诺阿分校的一个研究小组将使用新的天文观测结果、基于太空的恒星测量结果和恒星自转的计算机模型来确定它们的年龄。M矮星的准确年龄将有助于追踪银河系中元素的分布，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了解年轻的M矮星的快速自转和强大的磁活动，这将改进它们在许多波长的光发射的模型，这些光是围绕它们运行的任何行星的环境的重要因素。研究人员将把这个项目的方方面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结构不同的高中生，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完成一个项目，该项目基于从莫纳克亚上的望远镜获得的数据，并在完成项目期间接受为期六个月的持续指导。研究项目旨在开发基于M矮星自转的天文计时器，并研究M矮星自转、多重性、圆盘和前主序列演化之间的联系。它将利用新的观测、空间探测的结果和恒星旋转的模型来(1)建立两个太阳年龄的星系团(M67和Ruprecht147)中M矮星的旋转序列(回转计时器)，作为自旋下降模型的关键校准点；(2)为毕宿星制作质量旋转图，这是M矮星自旋模型的关键中间基准，对双星进行统一和更彻底的审查；(3)确认或驳斥贝塔-皮克托里斯移动群中前主序M矮星之间的恒星同伴和自转之间的关联，作为对磁盘锁定情景的测试；和(4)测量选定的M矮星双星中组件的质量、半径、亮度和磁场，以量化自转和磁活动对前主序演化的影响。这一奖项反映了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。

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.