Critical Tests of Stellar Evolution Theory

恒星演化理论的关键测试

• 批准号: 0406183
• 负责人: Guillermo Torres
• 金额: $ 28.97万
• 依托单位: Smithsonian Institution Astrophysical Observatory
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2004
• 资助国家: 美国
• 起止时间: 2004-07-01 至 2007-06-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0406183&HistoricalAwards=false
• 关键词: Critical; Tests; Stellar; Evolution; Theory

Despite significant advances in recent decades in our understanding of the evolution and internal structure of stars, many aspects of theory remain untested or have been shown to disagree with observations. Evolutionary models are widely used by astronomers to infer various properties of stars such as their masses, ages, or metallicities, but our confidence in these models is limited to some extent by those disagreements and by a lack of observational constraints. The validation of theory is best made through a detailed comparison with accurate measurements of quantities such as the stellar mass, the radius, the effective temperatures, or the luminosities, of stars in carefully selected binary systems of known chemical composition. However these determinations are not trivial to make with the required precision. In this project, high quality spectroscopic, photometric, or astrometric observations are being obtained and analyzed to make the determinations of the absolute stellar properties with relative errors, in the case of the masses and radii, at the current state-of-the-art, and to perform "critical tests" of stellar evolution theory. More than that, the goal is to provide so many observational constraints for a given binary system that only the most realistic sets of models (if any) may satisfy all the observations within the errors. Key binary systems are being identified that provide the best tests of the models, with particular emphasis on low-mass stars, evolved stars and very young (pre-main-sequence) stars for which virtually no constraints are available, as well as on stars with chemical compositions very different from the Sun (metal-poor).Broader Impact. This project is advancing our understanding of several poorly known areas of stellar astrophysics such as convection (mixing length theory, overshooting), internal structure, stellar rotation, mass loss, and tidal evolution, allowing much more reliable determinations of parameters such as the ages of stars. These stellar parameters have profound cosmological implications and provide a more solid framework for the study of the origin and evolution of substellar objects such as brown dwarfs and extrasolar planets, subjects of great interest for the public and scientists alike. The dissemination of the results to the scientific community, mainly in the form of peer-reviewed publications, is an integral part of this work. It provides excellent opportunities for training by integrating front-line research into the experience of learning, allowing students to actively participate in all aspects of the study of crucial binary systems.

尽管近几十年来我们对恒星演化和内部结构的理解取得了重大进展，但理论的许多方面仍未经检验，或者与观测结果不一致。演化模型被天文学家广泛用于推断恒星的各种特性，如质量、年龄或金属丰度，但我们对这些模型的信心在某种程度上受到这些分歧和缺乏观测约束的限制。理论的验证最好是通过与精确测量的数量进行详细的比较，如恒星质量、半径、有效温度或亮度，在精心选择的已知化学成分的双星系统中。然而，要以所需的精度做出这些决定并非易事。在这个项目中，正在获得和分析高质量的光谱、光度或天体测量观测结果，以便以目前最先进的技术确定质量和半径方面存在相对误差的绝对恒星特性，并对恒星演化理论进行“关键测试”。更重要的是，目标是为给定的双星系统提供如此多的观测约束，以至于只有最现实的模型集（如果有的话）才能满足误差范围内的所有观测。关键的双星系统正在被确定，为模型提供了最好的测试，特别强调低质量恒星、演化恒星和非常年轻的（主序前）恒星，这些恒星几乎没有任何限制，以及化学成分与太阳非常不同的恒星（金属含量低）。更广泛的影响。这个项目促进了我们对一些鲜为人知的恒星天体物理学领域的理解，比如对流（混合长度理论、超调）、内部结构、恒星旋转、质量损失和潮汐演化，使我们能够更可靠地确定恒星年龄等参数。这些恒星参数具有深远的宇宙学意义，并为研究诸如褐矮星和系外行星之类的次恒星天体的起源和演化提供了一个更坚实的框架，这些天体是公众和科学家都非常感兴趣的主题。向科学界传播结果，主要以同行评审出版物的形式，是这项工作的一个组成部分。它通过将一线研究与学习经验相结合，为培训提供了极好的机会，使学生能够积极参与关键二元系统研究的各个方面。