ATES simulations of the Neptune-sized planet HAT-P-11b, subject to varying stellar irradiation fields. The planet orbital distance is fixed to 0.053 AU. The different colors correspond to the host spectral types shown in Fig. 2. Shown are the radial profiles of the outflow total density (A); temperature (B); velocity (C), where a diamond symbol indicates where the outflow becomes supersonic; He fraction in the triplet state (E); and He I(2³S) number density (F). All profiles extend from the planet surface to the system’s Hill radius. For the M4 V case, the Hill radius exceeds the size of the stellar disk (past which the outflow profile is shown as a dotted line in panel F). Panel D shows the outflow pressure-temperature diagram; the resulting He I(2³S) transmission probability is shown in panel G.