On the detectability of habitable exomoons with Kepler-class photometry

Abstract

In this paper we investigate the detectability of a habitable-zone exomoon around various configurations of exoplanetary systems with the Kepler Mission or photometry of approximately equal quality. We calculate both the predicted transit timing signal amplitudes and the estimated uncertainty on such measurements in order to calculate the confidence in detecting such bodies across a broad spectrum of orbital arrangements. The effects of stellar variability, instrument noise and photon noise are all accounted for in the analysis. We validate our methodology by simulating synthetic lightcurves and performing a Monte Carlo analysis for several cases of interest. We find that habitable-zone exomoons down to 0.2 Earth masses may be detected and ~25,000 stars could be surveyed for habitable-zone exomoons within Kepler's field-of-view. A Galactic Plane survey with Kepler-class photometry could potentially survey over one million stars for habitable-zone exomoons. In conclusion, we propose that habitable exomoons will be detectable should they exist in the local part of the galaxy.Comment: Accepted for publication in the Monthly Notices of the Royal Astronomical Societ