Mapping the Instabilities of Massive Stars

绘制大质量恒星的不稳定性图

• 批准号: 1716436
• 负责人: Richard Townsend
• 金额: $ 31.65万
• 依托单位: University of Wisconsin-Madison
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2017
• 资助国家: 美国
• 起止时间: 2017-07-01 至 2021-06-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1716436&HistoricalAwards=false
• 关键词: Mapping; Instabilities; Massive; Stars

A plot of luminosity versus temperature for stars, known as the Hertzsprung-Russell (HR) diagram, has proven invaluable in our understanding of the stars. A star's age and its mass determine its position on such a diagram. At specific periods during a star's life, it may pulsate---actually get larger and smaller---as gas pressure outward and gravity inward are not quite in balance. This project aims to investigate the processes inside pulsating hot, massive stars. The investigator will use theory and numerical modeling to create a "map" on the HR diagram describing what might be going on inside stars for each combination of temperature and luminosity. The results will be made available to the public via a web portal, in addition to publication of results in the refereed literature. A female graduate student, already well along in her studies, will complete her PhD thesis with this funding.Once stars evolve past the main sequence of the HR diagram, they can undergo many episodes of pulsation. Cepheid variables are the best known and understood; they populate an area of the HR diagram known as the instability strip. The investigator describes many other instability strips and makes the case for other causes of instability in stars more massive than the classical Cepheids. For example, in addition to the radially symmetric pulsations of Cepheids, pulsation-rotation interactions and non-adiabatic pulsation are considered. The work will involve modifications to the MESA and GYRE computer codes, which the PI has developed.

恒星的光度与温度的关系图，被称为赫兹-罗素（HR）图，在我们理解恒星方面已经证明是非常宝贵的。 一颗星星的年龄和质量决定了它在这张图上的位置。 在星星生命的特定时期，它可能会脉动--实际上变得越来越小--因为向外的气体压力和向内的重力不太平衡。 该项目旨在研究脉动热，大质量恒星内部的过程。 研究人员将使用理论和数值建模在HR图上创建一个“地图”，描述每种温度和光度组合下恒星内部可能发生的事情。 除了在参考文献中公布结果外，还将通过门户网站向公众提供结果。 一位女研究生，已经沿着她的研究，将完成她的博士论文与这笔资金。一旦恒星演变过去的主要序列的人力资源图，他们可以经历许多插曲的脉动。 造父变星是最为人所知和理解的，它们占据了HR图中被称为不稳定带的区域。 研究者描述了许多其他的不稳定带，并提出了比经典造父变星质量更大的恒星不稳定的其他原因。 例如，除了造父变星的径向对称脉动，脉动旋转的相互作用和非绝热脉动被认为是。 这项工作将涉及修改PI开发的梅萨和GYRE计算机代码。

项目成果

Improved asymptotic expressions for the eigenvalues of Laplace’s tidal equations

拉普拉斯潮汐方程特征值的改进渐近表达式

• DOI: 10.1093/mnras/staa2159
• 发表时间: 2020
• 期刊: Monthly Notices of the Royal Astronomical Society
• 影响因子: 4.8
• 作者: Townsend, R H

Stability and pulsation of the first dark stars

• DOI: 10.1093/mnras/stab420
• 发表时间: 2020-10
• 期刊: Monthly Notices of the Royal Astronomical Society
• 影响因子: 4.8
• 作者: T. Rindler-Daller;K. Freese;R. Townsend;L. Visinelli

The Impact of White Dwarf Luminosity Profiles on Oscillation Frequencies

• DOI: 10.3847/2041-8213/aae70f
• 发表时间: 2018-10
• 期刊: The Astrophysical Journal Letters
• 作者: Francis Timmes;R. Townsend;E. Bauer;A. Thoul;C. Fields;W. M. Wolf

The effects of surface fossil magnetic fields on massive star evolution – II. Implementation of magnetic braking in mesa and implications for the evolution of surface rotation in OB stars

• DOI: 10.1093/mnras/staa237
• 发表时间: 2020-01
• 期刊: Monthly Notices of the Royal Astronomical Society
• 影响因子: 4.8
• 作者: Z. Keszthelyi;Z. Keszthelyi;Z. Keszthelyi;G. Meynet;M. Shultz;A. David-Uraz;A. ud-Doula;R. Townse

Modules for Experiments in Stellar Astrophysics (MESA): Pulsating Variable Stars, Rotation, Convective Boundaries, and Energy Conservation

• DOI: 10.3847/1538-4365/ab2241
• 发表时间: 2019-07-01
• 期刊: ASTROPHYSICAL JOURNAL SUPPLEMENT SERIES
• 影响因子: 8.7
• 作者: Paxton, Bill;Smolec, R.;Timmes, F. X.
• 通讯作者: Timmes, F. X.