A statistical primer on exoplanet detection methods

Historically, a lack of cross-disciplinary communication has led to the development of statistical methods for detecting exoplanets by astronomers, independent of the contemporary statistical literature. The aim of our paper is to investigate the properties of such methods. Many of these methods (both transit- and radial velocity-based) have not been discussed by statisticians despite their use in thousands of astronomical papers. Transit methods aim to detect a planet by determining whether observations of a star contain a periodic component. These methods tend to be overly rudimentary for starlight data and lack robustness to model misspecification. Conversely, radial velocity methods aim to detect planets by estimating the Doppler shift induced by an orbiting companion on the spectrum of a star. Many such methods are unable to detect Doppler shifts on the order of magnitude consistent with Earth-sized planets around Sun-like stars. Modern radial velocity approaches attempt to address this deficiency by adapting tools from contemporary statistical research in functional data analysis, but more work is needed to develop the statistical theory supporting the use of these models, to expand these models for multiplanet systems, and to develop methods for detecting ever smaller Doppler shifts in the presence of stellar activity.