Kepler’s hidden treasure - circumbinary Earths

Circumbinary planets have been shown to be more than just exotic curiosities. These astrophysical tools shed light on a variety of problems; they have tested the robustness of planet formation, provided some of the strongest evidence to date for planet migration, and helped answer fundamental questions in the physics of multiple star systems. However, discoveries of circumbinary planets to date are unfortunately sparse. The Kepler survey has discovered 11 transiting planets, but only large, gaseous ones. Eclipse timing variations have uncovered a similar number, but the planets are even more massive and questions have been raised over their validity. The remaining techniques have combined for less than half a dozen detections. I will present a way forward for the field by showing how we may detect small, super-Earth and even Earth-sized transiting circumbinary planets. I will demonstrate a novel algorithm that overcomes the fundamental problem of day-amplitude transit timing variations by incorporating them into the phase-folding of photometric data. This allows shallow transits to be coherently stacked, illuminating a detectable signal. Based on the natural predication for planets to be more abundant at smaller sizes, one may expect hundreds of small circumbinary planets to be lurking in the Kepler data alone - a potential gold mine. I will also cover the TESS and PLATO missions, and what is likely to be a golden era for these astrophysical gems.

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