Collaborative Research: A Fresh Look at M Dwarf Stars

合作研究：重新审视 M 矮星

基本信息

批准号：
2009355
负责人：
Philip Muirhead
金额：
$ 13.23万
依托单位：
Trustees of Boston University
依托单位国家：
美国
项目类别：
Standard Grant
财政年份：
2020
资助国家：
美国
起止时间：
2020-09-01 至 2024-08-31
项目状态：
已结题

来源：
https://www.nsf.gov/awardsearch/showAward?AWD_ID=2009355&HistoricalAwards=false
关键词：
Collaborative Research Fresh Look Dwarf

项目摘要

Over 70% of all stars are “M dwarfs”, which are much smaller, cooler, and less luminous than the Sun. A better understanding of their physical properties touches on galactic chemical evolution, the dynamics of the galaxy, stellar atmospheres, molecular astrophysics, star formation, planet formation, and exoplanet characterization. This group will advance our understanding by uniting the best physical models of stellar interiors and atmospheres and testing them with high-quality observations. These projects have an important training component, as much of the work will be done by graduate students at UC Santa Cruz, Arizona State University, and Boston University. Undergraduate students will also be involved in the research, and the team will create a new curriculum and training materials, including a webinar for students to learn about future careers. The team will carry out a thorough modeling study of M dwarf atmospheres, interiors, and evolution. Previous work on M dwarf physics has used methods and codes devised for more massive stars, with workers moving down in mass to M dwarfs. This group will use modeling tools developed for brown dwarfs, just lower in mass than the M stars, and then move up in mass to model these objects. M dwarfs and brown dwarfs share many properties, like molecule-dominated atmospheres and partially degenerate interiors. This team will use spectral "retrieval" models for M stars, a fully Bayesian data-driven method, to yield best-fit temperature structures and abundances that are not bound to pre-computed atmosphere grids. They will focus on benchmark, well-studied M stars in orbit around Sun-like primaries. Based on the outcomes of this work, they will then compute a large grid of radiative-convective model atmospheres to yield trends in temperature, gravity, and metallicity, which will be of use to the entire astronomical community. Such models will also serve as the upper boundary conditions for new self-consistent M dwarf evolution models with MESA, which will include a new hydrogen equation of state. This will allow them to pursue detailed comparisons with previous theoretical and observational work on M dwarf atmospheres, their locations on the H-R diagram, and observed mass-radius relations.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.

超过70％的恒星是“ M矮人”，它们比太阳小得多，凉爽且发光。更好地理解它们的物理特性，涉及银河化学演化，银河系的动力学，恒星大气，分子天体物理学，恒星形成，行星形成和系外行星的表征。该小组将通过团结出色的内饰和气氛的最佳物理模型，并通过高质量的观察来提高我们的理解。这些项目具有重要的培训组成部分，大部分工作将由加州大学圣克鲁斯分校，亚利桑那州立大学和波士顿大学的研究生完成。本科生还将参与研究，团队将创建新的课程和培训材料，包括供学生学习未来职业的网络研讨会。该团队将对M矮人的气氛，内饰和进化进行彻底的建模研究。以前关于M矮人物理学的工作使用了为更大的恒星设计的方法和代码，工人在群众中向下移动到M矮人。该小组将使用针对棕色矮人开发的建模工具，质量比M恒星低，然后以质量向上移动以对这些对象进行建模。矮人和棕色矮人具有许多特性，例如分子主导的大气和部分退化的内饰。该团队将使用光恒星（一种完全贝叶斯数据驱动的方法）使用光谱“检索”模型，以产生最佳拟合温度结构和抽象，这些结构与预先计算的大气网格无关。他们将专注于基准，研究的M恒星在阳光般的初级周围的轨道上。然后，根据这项工作的结果，他们将计算大量的辐射感染模型大气层的网格，以产生温度，重力和金属性的趋势，这将用于整个天文学群落。此类模型还将用作带有MESA的新自洽M矮化演化模型的上边界条件，其中将包括一个新的状态氢方程。这将使他们能够与以前关于M矮人气氛的理论和观察性工作进行详细比较，在H-R图上的位置以及观察到的Mass-Radius关系。该奖项反映了NSF的法定任务，并认为通过基金会的知识分子的智力和更广泛的影响，可以通过评估来获得支持，并被认为是值得的。