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Tidal heating converts mechanical energy of tidal deformation into internal heat through tidal dissipation. Sustained orbital eccentricity or a spin axis tilted relative to the orbital plane's perpendicular can maintain changing tidal deformation and heat an exoplanet interior. Thus synchronous rotation alone does not eliminate tidal heating.

A departure of transit arrival times from a constant-period ephemeris can reveal gravitational interactions with other bodies. Dynamical fits may constrain an exoplanet mass independently of transit depth, providing a mass to combine with radius for exoplanet interior models.

The Very Large Telescope is an observatory array at Paranal with four $8.2$-metre Unit Telescopes and four movable $1.8$-metre Auxiliary Telescopes. The Unit Telescopes can observe independently; selected beams can also be combined in an astronomical interferometer. Combining beams coherently changes the angular information available and requires an appropriate observing instrument.^[ref]

For exoplanets, adaptive optics helps concentrate light for exoplanet direct imaging, while instruments such as CRIRES resolve molecular spectral lines. Spatial separation and Doppler shift provide complementary ways to distinguish a faint planet from its host star. The capability belongs to the telescope-plus-instrument combination, rather than to aperture size alone.