Stellar variability in the MOA database

Abstract

Research undertaken for this thesis aimed to detect and identify stellar variability in the database of the Japan/New Zealand MOA collaboration. The database of stars collected by the MOA project provided an extensive source of raw data for analysis. Detection of stellar variability was performed by several C++ programs created by the author, which incorporated the Welch and Stetson variability index, the Schwarzenburg-Czerny period folding program, a microlensing modelling program and a transit, detection program. The search for stellar variability produced 83 Cepheid variables, 265 long period variables, 59 eclipsing binaries and 6 potential microlensing events. Sixteen potentially interesting variations that could correspond to planetary transits were also detected. The folded lightcurve of one of the potential transits was categorised as a 'very interesting transit' and 15 were categorised as 'interesting transits'. The search for planetary transits ultimately proved unsuccessful, however, a detailed statistical study of the MOA data revealed several alterations concerning observational procedures which could be made to optimise the MOA data for any future search for planetary transits.