Spectral transmission of the He triplet for several planets. For HAT-P-32 b (a), WASP-69 b (b), GJ 1214 b (c), and WASP-76 b (d) (with different y-axis scales). Data points and their respective error bars are shown in black (adapted from Czesla et al. 2022, Nortmann et al. 2018, Orell-Miquel et al. 2022, and Casasayas-Barris et al. 2021, respectively). Wavelengths are given in vacuum. The best-fit simulations are shown with red curves. For HAT-P-32b, the best fit corresponds to a temperature of 12500 K, a mass-loss rate of 1.4 ×10¹³ g s⁻¹, and a H/He mole-fraction of 99/1; for WASP-69 b, the fit corresponds to a temperature of 5375 K, Ṁ = 10¹¹ g s⁻¹ and H/He = 98/2; for GJ 1214 b, a temperature of 3625 K, Ṁ = 6.3 × 10¹⁰ g s⁻¹, and H/He = 98/2; and for WASP-76 b, a temperature of 9500 K, Ṁ = 1.2 × 10¹² g s⁻¹, and H/He = 98/2. Other transmission models are shown (in blue) when the gas radial outflow velocity was not included. The positions of the helium lines are given by vertical dotted (weak) and dash-dotted (strong) lines.