The ‘hot Jupiters’ that abound in lists of known extrasolar planets are thought to have formed far from their host stars, but migrate inwards through interactions with the proto-planetary disk from which they were born, or by an alternative mechanism such as planet–planet scattering. The hot Jupiters closest to their parent stars, at orbital distances of only 0.02 astronomical units, have strong tidal interactions, and systems such as OGLE-TR-56 have been suggested as tests of tidal dissipation theory.
Hellier et al. 2009, Nature, 460, 1098
