Hunting for red supergiant binary systems in the ultra-violet

Massive stars are uniquely important cosmic engines and are responsible for the production of gravitational wave progenitors. Throughout their lives - via intense stellar winds - and as they die - via core-collapse supernova explosions - massive stars shape their chemical and kinematic environment. The effects of binary evolution and interactions are one of the major uncertainties in our understanding of the lives of massive stars and predicting their endpoints. This is particularly true of the red supergiant (RSG) phase of evolution: the final evolutionary phase before supernova for the majority of massive stars. The new, high-spatial resolution, UltraViolet Imaging Telescope survey of the Magellanic Clouds provides a unique method to identify and characterise RSG binary systems where the - normally dominant - RSG star is extremely faint. We present our first results in the Small Magellanic Cloud, where we examine the binary nature of over 500 RSGs and determine the initial binary fraction of SMC RSGs to be 18.8 ± 1.5%. Stellar parameters for both components are determined and the mass-ratio distribution of the SMC RSG binary population is studied. We place these results in an evolutionary context by comparing with multiplicity statistics at different evolutionary phases.