The colour of noise in SuperWASP data and the implications for finding extra-solar planets

Abstract

A recent study demonstrated that there is significant covariance structure in the noise on data from ground-based photometric surveys designed to detect transiting extrasolar planets. Such correlation in the noise has often been overlooked, especially when predicting the number of planets a particular survey is likely to find. Indeed, the shortfall in the number of transiting extrasolar planets discovered by such surveys seems to be explained by co-variance in the noise. We analyse SuperWASP (Wide Angle Search for Planets) data and determine that there is a significant amount of correlated systematic noise present. After modelling the potential planet catch, we conclude that this noise places a significant limit on the number of planets that SuperWASP is likely to detect; and that the best way to boost the signal-to-noise ratio and limit the impact of co-variant noise is to increase the number of observed transits for each candidate transiting planet.