Collaborative Research: Fundamental Properties of Local Subdwarfs

合作研究：当地亚矮星的基本性质

• 批准号: 0205815
• 负责人: Timothy Beers
• 金额: $ 7.48万
• 依托单位: Michigan State University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2002
• 资助国家: 美国
• 起止时间: 2002-07-01 至 2006-06-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0205815&HistoricalAwards=false
• 关键词: Collaborative; Research; Fundamental; Properties; Local

AST-0205815 Beers, Timothy C.Dr. Beers is awarded funds at Michigan State University to work with collaborators at the University of Texas at Austin and Ohio State University. This team will lay the groundwork for a more detailed understanding of how our Milky Way galaxy formed and evolved. Models of galaxy formation and evolution depend on understanding the motions and chemical enrichment of local main-sequence stars that are far lower in heavy elements than ordinary stars, and how these stars compare to globular cluster stars. The known sample of these "subdwarfs" is very small.Dr. Beers and collaborators will study a new sample of these subdwarf stars in theGalaxy's halo and thick disk; this sample represents a huge increase over the number of subdwarfs previously studied. The investigators will obtain accurate and self-consistent measures of temperature, reddening, and composition for a critically selected sample of approximately 150 subdwarfs identified in recent surveys for metal-poor stars. They will also apply theoretical models to explore the dependence of the main-sequence luminosity on detailed stellar chemical composition. The results will be used to improve the temperature and abundance scales of globular cluster main sequences for comparison to spectroscopic determinations on the giant branch, and to thus determine the relative ages and distances of globular clusters.

AST-0205815比尔斯，蒂莫西C比尔斯博士被授予资金在密歇根州立大学与合作者在得克萨斯大学奥斯汀分校和俄亥俄州州立大学。 这个团队将为更详细地了解我们的银河系如何形成和演化奠定基础。星系形成和演化的模型依赖于理解局部主序星的运动和化学富集，这些恒星的重元素远远低于普通恒星，以及这些恒星与球状星团恒星的比较。这些"亚矮星"的已知样本非常小。比尔斯博士和合作者将研究银河系晕和厚盘中这些亚矮星的新样本;这个样本比以前研究的亚矮星数量有了巨大的增加。 研究人员将获得精确和自洽的温度，红化和成分的测量结果，这些测量结果是在最近的贫金属恒星调查中确定的大约150个亚矮星的严格选择的样本。他们还将应用理论模型来探索主序星光度对详细恒星化学成分的依赖性。 这些结果将用于改进球状星团主序列的温度和丰度尺度，以便与巨型分支上的光谱测定进行比较，从而确定球状星团的相对年龄和距离。