Transit Timing Variations

If an exoplanet transits it's host star along our line of sight, then a planet on an unperturbed Keplerian orbit will transit with a fixed, predictable period. When an exoplanet orbit is perturbed by interactions with other planets, the perturbed orbits can give rise to transit timing variations (TTVs).These TTVs can be used to infer the presence of unseen companions, or if the companion also transits, can be used to provide precise information on the mass of the companion planet.

TA researchers have been intimately involved in the study of TTVs from their initial conception, the first attempts at measurement from the ground, their first successful implementation using the Kepler spacecraft, and are involved in on-going research to characterize multiple exoplanetary systems using this technique.