1D marginalized posterior distributions for key parameters in the atmospheric fit to the 16-bin MIRI LRS eclipse spectrum. The top-left panel shows the derived posterior on total surface pressure (solid black line), compared to implicit prior (dotted black line). The top-right panel shows pressure–temperature profiles sampled from the posterior. The climate-constrained inversion places a 95% upper limit of 0.6 bar on the surface pressure. If an atmosphere is present, a tenuous CO₂ (or O₂) dominated atmosphere is most probable.