Critical Tests Of Stellar Evolution Theory

恒星演化理论的关键测试

• 批准号: 1509375
• 负责人: Guillermo Torres
• 金额: $ 50.3万
• 依托单位: Smithsonian Institution Astrophysical Observatory
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2015
• 资助国家: 美国
• 起止时间: 2015-09-01 至 2019-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1509375&HistoricalAwards=false
• 关键词: Critical; Tests; Stellar; Evolution; Theory

The principal investigator will accurately measure the global properties of stars, like their mass, size, brightness, temperature, and composition. He will use these measurements to improve the ability of computer models to predict stellar properties at various stages in their life cycles. Such models are the foundation of our understanding of how our Milky Way Galaxy and its member stars (including our Sun) reached their present state. They also tell us about the timescale for planet formation, which has a significant impact on how well we understand the origin of planets like our own. Despite advances in recent decades, stellar models still show some significant disagreements with observations. The measurements obtained by this project will help to improve stellar physics, and it will offer valuable opportunities to engage students in all aspects of scientific research, providing support for two summer undergraduate students each year.The project will measure the fundamental properties of carefully-selected target stars in eclipsing or astrometric binary systems, which will provide the strongest constraints on theory. The sample includes low-mass stars, which have been shown to often be larger and cooler than predicted by models, for reasons that are still unclear. The main goal is to obtain highly accurate measurements of the absolute masses, radii, effective temperatures, luminosities, chemical composition, and other properties of the components, aiming at relative precisions of 1-2% in the masses and radii. The observational component of the project will include photometric light curves, high-resolution spectra, and long-baseline interferometry. Specific aspects of theory that will be tested include convection (mixing length approximation, overshooting), tidal effects that lead to rotational synchronization and orbital circularization, and the effects of magnetic activity and spots on the absolute stellar properties.

首席研究员将准确测量恒星的整体性质，如质量，大小，亮度，温度和成分。 他将利用这些测量来提高计算机模型预测恒星生命周期各个阶段性质的能力。这些模型是我们理解银河系及其成员恒星（包括我们的太阳）如何达到目前状态的基础。它们还告诉我们行星形成的时间尺度，这对我们如何理解像我们这样的行星的起源有重大影响。尽管近几十年来取得了进展，恒星模型仍然显示出与观测的一些重大分歧。该项目获得的测量结果将有助于提高恒星物理学，并将提供宝贵的机会，让学生参与科学研究的各个方面，每年为两名暑期本科生提供支持。该项目将测量食或天体测量双星系统中精心挑选的目标恒星的基本性质，这将提供最强的理论约束。样本包括低质量恒星，这些恒星通常比模型预测的更大，更冷，原因尚不清楚。 主要目标是获得绝对质量、半径、有效温度、光度、化学成分和其他成分性质的高精度测量，目标是质量和半径的相对精度为1-2%。 该项目的观测部分将包括光度学光变曲线、高分辨率光谱和长基线干涉测量。将测试的理论的具体方面包括对流（混合长度近似，过冲），潮汐效应，导致旋转同步和轨道圆化，以及磁活动和绝对恒星属性上的斑点的影响。