Studies of the RR Lyrae Variables in the Galactic Field and Globular Clusters and the Morphology of the Horizontal Branch

津恩博士会测量金属丰度和径向速度 大约400颗天琴座RR型变星。 这些数据将改善我们的 运动学对金属丰度的依赖性的知识， 我们银河系的晕和厚盘中的恒星种群 银河系。 这将限制早期进化的模型 银河系。 两个球状星团是最具金属元素的- 被认为包含RR Lyonian变量的丰富集群，将是 观察 这些数据和计算的合成水平 分支模型将有助于解决 富含金属的天琴座RR型变星 彩色星等图将是 为10个球状星团建造的， 银河中心 这些数据将对年龄设定上限 可能存在的变化，这反过来又会限制模型 银河系演化。 两个最流行的，和竞争，形成的图片， 我们银河系的晕预测了 铁氢丰度比和平均转动惯量 绕银河系中心的速度 有相当多的争论 当前数据是否支持任一图片而不是另一图片。 津恩博士设计了一个观测项目 将排除两种模型中的一种。

Dr. Zinn will measure the metal abundances and radial velocities of about 400 RR Lyrae variable stars. These data will improve our knowledge of the dependence of kinematics on metal abundance in the halo of our Galaxy and the populations of stars in the thick disk of the Galaxy. This will constrain models of the early evolution of the Galaxy. Two globular clusters, which are the most metal- rich clusters thought to contain RR Lyrae variables, will be observed. These data and computations of synthetic horizontal branch models will help resolve the enigma of the origin of the metal-rich RR Lyrae variables. Color magnitude diagrams will be constructed for about 10 globular clusters of stars close to the Galactic Center. These data will set an upper limit on the age variations that may be present, which in turn will constrain models of galactic evolution. The two most popular, and competing, pictures of the formation of the halo of our Galaxy predict very different relationships between the abundance ratio of iron to hydrogen and the mean rotational velocity about the Galactic Center. There is considerable debate whether the present data support either picture over the other. Dr. Zinn has designed an observational project which he expects will rule out one or the other of the two models.