THE COMPOSITION OF GALACTIC GLOBULAR CLUSTERS

“银河系球状星团的组成”AST-0097955在探索银河系的早期历史时，我们高度重视我们所能识别的最古老的恒星与目前正在形成的恒星之间的比较。当我们可以将注意力限制在尚未从主序演化出来的恒星上，从而用核燃烧的产物污染它们的大气时，分析就简化了。在球状星团中可以找到古老的、未演化的恒星的良好样本，但它们很微弱，只有在有了像凯克10M望远镜这样的大型地面仪器时，我们才能对这些恒星进行足够详细的研究，以便进行基准比较。在这次颁奖过程中，PI将利用Keck I望远镜的高分辨率光谱能力，在银河系光晕群中的几个球状星团的岔口附近获得主序恒星的光谱。这些光谱将被分析并确定化学丰度，长期目标是对银河系的化学演化施加定量限制。

" The Composition of Galactic Globular Clusters "AST- 0097955In probing the early history of the Milky Way system, high weight is given to comparisons between the oldest stars that we can recognize and those that are being formed at the present time. The analysis is simplified when we can restrict attention to stars that have not yet evolved off the main sequence thereby contaminating their atmospheres with the products on nuclear burning. Good samples of ancient, unevolved stars can be found in globular clusters but they are faint and it is only with the availability of large ground-based instruments like the Keck 10m telescopes that we can study these stars in sufficient detail to make benchmark comparisons. During the course of this award the PI will take advantage of an opportunity to use the high-resolution spectroscopic capability of the Keck I telescope to obtain spectra of main sequence stars near the turnoff in several globular clusters among the halo population of the Milky Way. These spectra will be analyzed and chemical abundances determined with the long-term objective of putting quantitative constraints on the chemical evolution of the Milky Way Galaxy.