Top: temperature (black solid line) and pressure (red dashed line) profiles as a function of radius r in units of R_pl for a 5 M_⊕ and 4 R_⊕ planet with T_eq=1000 K, orbiting an early K-type star (see Table 1). The right axis indicates the pressure scale. Middle: λ^∗ (black solid line) and (red dashed line) profiles as a function of radius r in units of R_pl. The horizontal lines mark the critical values of the Jeans escape parameter in the hydrostatic case: 1.5, 15, and 30. The blue dotted lines show the λ^∗ and profiles calculated assuming that the whole atmosphere is made of atomic hydrogen. The filled circle indicates the Λ value (see Sect. 3). Bottom: υ_th (black solid line) and υ_hy (red dashed line) profiles in km s^-1.