Origin and detectability of co-orbital planets from radial velocity data

Abstract

We analyse the possibilities of detection of hypothetical exoplanets in co-orbital motion from synthetic radial velocity (RV) signals, taking into account different types of stable planar configurations, orbital eccentricities and mass ratios. For each nominal solution corresponding to small-amplitude oscillations around the periodic solution, we generate a series of synthetic RV curves mimicking the stellar motion around the barycentre of the system. We then fit the data sets obtained assuming three possible different orbital architectures: (a) two planets in co-orbital motion, (b) two planets in a 2/1 mean-motion resonance (MMR) and (c) a single planet. We compare the resulting residuals and the estimated orbital parameters.