Collaborative Research: Stellar Physics from Cluster-Wide Samples in Globular Clusters

合作研究：来自球状星团全星团样本的恒星物理

• 批准号: 0507697
• 负责人: Michael Bolte
• 金额: --
• 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: 2005
• 资助国家: 美国
• 起止时间: 2005-07-15 至 2010-06-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0507697&HistoricalAwards=false
• 关键词: Collaborative; Research; Stellar; Physics; Cluster

AST-0507785 / AST-0507697Eric Sandquist / Michael BolteSan Diego State University / University of California Santa CruzCollaborative Research: Stellar Physics from Cluster-Wide Samples in GlobularStar ClustersABSTRACTA series of observational tests of theories of the structure and evolution of low mass stars will beperformed. Specifically, counts of globular cluster stars (i.e., luminosity functions) will beemployed to determine evolutionary timescales. Also, internally-consistent photometry will bemeasured to compare stellar properties (luminosity, temperature) at different phases of evolutionand at the same points of evolution across different clusters. Three aspects of the cluster colormagnitudediagrams will be examined: 1) The epoch of red giant branch ascent, including red giantevolutionary timescales, the red giant branch bump (its luminosity and sharpness), and thelocation of the red giant branch-tip; 2) horizontal branch and asymptotic giant branch morphologies,distributions, and evolution; and 3) blue stragglers and their radial distributions, distributions on thecluster color magnitude diagrams, and the presence of unusual blue straggler populations. Thestatistical nature of these investigations requires quality photometry of large samples of cluster starswhich will be extracted from previously obtained wide field (for cluster outskirts) and highresolution (for cluster cores) images obtained at national and international observatories telescopes(plus archival images, including the Hubble Space Telescope where possible). Novel (within theastronomical community) statistics will also be employed in the analysis to assesssignificance/confidence levels of trends and relations.Undergraduate and Master's students at San Diego will be heavily involved in this work - both withthe reduction and analysis of the astronomical data and the application of advanced statisticalmethods. The training of a graduate student at UCSC is also supported here. The final photometrywill also be made publicly available.

eric Sandquist / Michael BolteSan Diego州立大学/加州大学圣克鲁斯分校合作研究：球状星团中全星团样本的恒星物理摘要将进行一系列关于低质量恒星结构和演化理论的观测测试。具体来说，球状星团恒星的计数（即光度函数）将被用来确定演化的时间尺度。此外，将测量内部一致的光度，以比较不同演化阶段和不同星团同一演化点的恒星特性（光度、温度）。星团色星等图的三个方面将被研究：1)红巨星分支上升的时代，包括红巨星进化的时间尺度，红巨星分支凸起（其亮度和锐度），以及红巨星分支尖端的位置；2)水平分支与渐近巨分支形态、分布与演化；3)蓝离散星及其径向分布，星团色星等图上的分布，以及不寻常的蓝离散星种群的存在。这些调查的统计性质需要对星团恒星的大样本进行高质量的光度测定，这些样本将从先前获得的宽视场（用于星团外围）和高分辨率（用于星团核心）图像中提取，这些图像来自国家和国际天文台望远镜（加上档案图像，包括哈勃太空望远镜）。新颖的（天文学领域内的）统计数据也将用于分析，以评估趋势和关系的显著性/置信度。圣地亚哥大学的本科生和硕士生将大量参与这项工作，包括对天文数据的简化和分析，以及先进统计方法的应用。加州大学圣迭戈分校的研究生培训也得到了这里的支持。最终的光度测量结果也将向公众公布。