Thesis Supervisor: Daniel Bramich

Abstract

The study of globular clusters finds its relevance in the context of the origin, structure and evolution of the Galactic halo. There are ~150 globular clusters in our Galaxy for which their fundamental properties, such as distance, metallicity, age and kinematics, are known. We have been undertaking an observational program to discover the populations of variable stars in such clusters, specifically the RR Lyrae stars. These cluster variables pulsate in a predictable way enabling the measurement of their fundamental properties from their lightcurves, which in turn provide estimates of similar quantities for the host cluster.

Generally, the variable population of globular clusters is not well studied, and recently the technique of difference imaging has enabled high precision photometry of stars in the central regions of the clusters, leading to the discovery of many more variables. The student project would include observational work (on telescopes in India, Mexico, Venezuela or elsewhere), data reduction, lightcurve analysis and cluster analysis. We have data sets in various stages of analysis which may also be worked upon.

Other variable stars of interest would include SX Phoenicis stars (rapid pulsators), and eclipsing binaries. We also have data on open clusters for which the variable star content has not been analysed.

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