Comparison of retrieved PT profiles using the N. Madhusudhan & S. Seager (2009) and T. Guillot (2010) parameterizations for the dayside emission spectrum of LTT 9779 b. Solid curves show the median PT profiles, with shaded regions indicating the 1σ confidence intervals. The dashed lines mark the approximate adiabatic temperature gradient for LTT 9779 b (∼500 K per decade in pressure; V. Parmentier & T. Guillot 2014), representing the maximum physically allowed temperature gradient for a stable convective atmosphere. While the N. Madhusudhan & S. Seager (2009) PT profile remains within this physical limit across all pressures and temperatures, the Guillot parameterization yields solutions that exceed the adiabatic gradient, especially over the ∼1200–2200 K range. Due to this thermally unstable solution for the Guillot profile, we adopt the N. Madhusudhan & S. Seager (2009) PT parameterization for all analyses.