RR Lyrae Stars and the Oosterhoff Dichotomy

史密斯，贺拉斯“RR Lyrics明星奥斯特霍夫二分法“AST-9986943博士。史密斯提议研究为什么球状星团中存在两组天琴座RR型恒星（所谓的“奥斯特霍夫二分法”）。 这类恒星是星族II恒星和星团的主要距离标准。 因此，拟议中的工作将直接有助于阐明加速宇宙的性质。 一个光度和光谱计划将进行，以确定物理参数，如金属量，被怀疑与奥斯特霍夫的集团成员关系。 除了这个主要的重点，史密斯博士还将研究的形状和振幅的调制RR天琴座光变曲线（Blazhko效应）。该项目的资金由美国国家科学基金会计划恒星天文天体物理学（AST/SAA）提供。

Smith, Horace"RR Lyrae Stars & the Oosterhoff Dichotomy"AST-9986943Dr. Smith proposes to investigate the reasons why two groups of RR Lyrae stars exist among globular clusters (the so-called "Oosterhoff Dichotomy"). Such stars are the primary distance standard for Population II stars and clusters. The proposed work will therefore contribute directly to elucidating the nature of the accelerating universe. A photometric and spectroscopic program will be undertaken in order to determine the physical parameters such as metallicity that are suspected to correlate with Oosterhoff's group membership. In addition to this main focus, Dr. Smith will also examine the modulation of the shape and amplitude of RR Lyrae light curves (Blazhko effect).Funding for this project was provided by the NSF program for Stellar Astronomy & Astrophysics (AST/SAA).