Assessing the detectability of tidal deformation in close-in giant exoplanets with JWST and Ariel

Tidal forces can significantly deform close-in exoplanets, providing a unique probe of their internal structure. The degree of deformation depends on a planet’s internal mass distribution and is quantified by the fluid Love number ($h_{2f}$), which describes the planetary response to external gravitational perturbations. While interior models based solely on mass and radius are often highly degenerate, Love numbers provide a complementary observable that can help break these degeneracies and constrain a planet’s central mass concentration.

In this work, we investigate the capability of current and future space missions, including JWST and Ariel, to detect tidal deformation in close-in giant exoplanets. Using the ultra-hot Jupiter WASP-76b as a benchmark target, we perform end-to-end simulations of phase-curve observations to evaluate whether tidal deformation signatures can be recovered from realistic datasets and to assess the precision with which the Love number can be constrained.

Our results show that tidal deformation in close-in giant exoplanets may be detectable with both JWST and Ariel, opening a new avenue for probing exoplanet interiors through photometric observations. Combined with interior structure models, these measurements could provide novel constraints on the internal mass distribution of close-in giant planets.