Research Information System
ASTROPHYSICAL JOURNAL, vol.994, no.2, 2025 (SCI-Expanded, Scopus)
The survival of volatile-rich atmospheres on close-in exoplanets challenges classical escape models. We identify a fully classical, interior-driven correction: thermoelastic contraction of the planetary mantle slightly increases the gravitational binding energy and the effective escape threshold. Incorporating pressure and temperature-dependent elastic deformation, we define a dimensionless suppression index Xi equivalent to(1-& varepsilon;V/3)-1/2 that links interior strain to escape dynamics. Across super-Earth and sub-Neptune regimes, realistic volumetric strains (& varepsilon;V similar to 10-3-10-2) enhance the escape velocity by 0.02%-0.17%, yielding less than or similar to 1% reductions in energy-limited mass-loss rates. Critically, the Jeans regime amplifies this effect through its exponential sensitivity to vesc: for representative super-Earth parameters, thermoelastic contraction alone suppresses the Jeans escape rate by up to similar to 18%. This establishes mantle elasticity as a small but physically robust correction to escape theory and a novel interior-atmosphere coupling channel. For instance, in the case of K2-18b, the predicted contraction-induced signal corresponds to similar to 30 ppm at 1.4 mu m, within the reach of JWST/NIRSpec in similar to 5 transits. We outline observational tests-particularly with JWST and ARIEL-where high signal-to-noise transmission spectroscopy could, in favorable cases, probe these suppression signatures and place constraints on deep planetary structure.