This award will support an observational program to compare various techniques for the determination of ages in several nearby star clusters. Currently, a number of different techniques are used for cluster ages, and they each suffer from various random and systematic errors that limit their use for finding absolute (as opposed to relative) ages. This group will investigate the accuracy and size of errors for four different techniques: (1) comparison of stellar data against theoretical models, (2) the mass-dependence of lithium abundances, (3) the decline of rotation rates with time, and (4) the relation between age and magnetic activity. The goal is to assess the accuracy of each technique and understand how to translate ages from one technique to the age scale from the others.
Improvements in the accuracy of stellar ages should have broad implications for understanding the history of stellar populations and the evolution of our Milky Way Galaxy. This project will provide many research opportunities for undergraduate students, especially through an ongoing partnership with Fisk College. The data from this project will also be used as calibrating data for future telescope surveys.