Comparative stability diagrams for 1 M_⊕ and 10 M_⊕ planets as functions of logarithms of stellar flux (horizontal axis) and surface pressure (vertical axis). The efficiency parameter controlling advective heat transport ε_eff take the values (from bottom to top). Left column: case without sensible heating (ε_sen = 0). Right column: case with efficient sensible heating (ε_sen = 1.0). The stellar flux is normalised by the modern Earth’s value F_⊕ = 1366 W m⁻², and the surface pressure is given in bar. The acronyms “E” and “SE” are employed for “Earth” and “Super-Earth”, and designate the 1 M_⊕ and 10 M_⊕ planets, respectively. Colours indicate the stability of the steady state obtained in the two cases, similarly as in Fig. 10. These plots are obtained by solving Eq. (65) (L_adv = +∞, top panels) and Eq. (78) (other panels) with κ_L = 8.5 × 10⁻⁵ m² kg⁻¹ and parameters values given by Table 2 for the Earth-sized planet. In the case of the 10 M_⊕ planet, the planet’s radius and mass are set to M_p = 10 M_⊕ and R_p= 1.88 R_⊕, respectively. Data computed by Wordsworth (2015) from GCM simulations (Fig. 12) are included in the middle right panel for comparison and indicate the region of atmospheric stability for the 1 M_⊕ planet (red dots) and both planets (violet dots), and the region of atmospheric collapse (small blue dots).