Collaborative Research: A Fresh Look at M Dwarf Stars

合作研究：重新审视 M 矮星

• 批准号: 2009592
• 负责人: Jonathan Fortney
• 金额: $ 35.86万
• 依托单位: University of California-Santa Cruz
• 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=2009592&HistoricalAwards=false
• 关键词: Collaborative; Research; Fresh; Look; Dwarf

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％的恒星是比太阳更小，凉爽，较少的发光。星球的形成和系外行星的特征。搜索将创建一个新的课程和培训材料，其中包括供学生了解未来职业的网络研讨会使用为棕色矮人开发的建模工具，在Muss中较低，并且在模型thesel Thects中移动。数据驱动的方法是最佳的温度结构，并且在预先计算的大气中没有结合。 ，他们将计算大型的格式交流大气。 Mesa，氢，这将使他们能够与以前的理论和观察性工作进行详细的比较通过基金会的智力优点和更广泛的审查标准进行评估，人们对矫正的态度进行了支持。