Detecting Tidal Orbital Decay with PLATO

Kurzfassung

Exoplanets orbiting close to their host stars are expected to interact tidally with their star. This tidal interaction should result in a transfer of angular momentum from the planetary orbit to the stellar spin. This leads to the planet spiralling in towards the star as its orbit decays. Over baselines of a decade or more, this is expected to lead to an observable change in the transit timing of short-period hot Jupiters orbiting Sun-like stars, as the orbit shrinks. The time scale of the decay (and of many other tidal processes) is determined by the stellar tidal quality factor (Q’*), which is a poorly-understood, and difficult to measure quantity. PLATO’s high precision and near continuous coverage are expected to enable the detection of tidal decay and measurement of Q’* in several systems. When combined with accurate stellar ages, we will be able to build a picture of how tidal forces influence planetary systems throughout their lifetimes.