Determine the stability of deep non-convective envelope regions

Determine whether non-convective structures at the bases of hydrogen-dominated sub-Neptune envelopes are stable against three-dimensional hydrodynamic and dynamical effects, including possible episodic convection or storms that could transport heavy species into observable atmospheric layers.

Background

The paper predicts deep non-convective regions generated by molecular-weight gradients from silicate condensation. These regions are central to the calculated thermal profiles, radii, and atmospheric compositions, but the calculations assume hydrostatic equilibrium and do not include envelope hydrodynamics.

The authors note that circulation studies of water-condensation-induced non-convective regions address substantially cooler and lower-pressure conditions. They therefore identify the three-dimensional stability of the high-temperature, high-pressure regions considered here as unresolved, particularly because intermittent convection could release high-mean-molecular-weight material into observable atmospheric layers.