RR Lyrae Stars and the Oosterhoff Dichotomy

Michigan State University, East Lansing MI

Investigators

Abstract

Smith, Horace "RR Lyrae Stars & the Oosterhoff Dichotomy" AST-9986943 Dr. 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).