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，我们非常重视比较我们所能识别的最古老的恒星和目前正在形成的恒星。当我们可以把注意力限制在那些还没有脱离主序星的恒星上，从而使它们的大气层受到核燃烧产物的污染时，分析就简化了。在球状星团中可以找到古老的未进化恒星的良好样本，但它们很微弱，只有使用大型地面仪器，如凯克10米望远镜，我们才能足够详细地研究这些恒星，以进行基准比较。在这个奖项的过程中，PI将利用一个机会，使用凯克一号望远镜的高分辨率光谱能力，以获得银河系晕群中几个球状星团中关闭附近的主序星光谱。将对这些光谱进行分析，并确定化学丰度，长期目标是对银河系的化学演化进行定量限制。

" 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.