HST-COS Lyman-α profiles of GJ 436 observed during Visit D after airglow decontamination (color spectra), binned to Doppler velocity intervals of 7km s⁻¹. The reference out-of-transit spectrum is plotted for comparison as a black spectrum against each exposure of Visit D. The regions shaded in gray correspond to: I) the reference far blue wing [−250, −120] km s⁻¹; II) the blue wing [−120, −40] km s⁻¹; III) the line core absorbed by the ISM [−30, +10] km s⁻¹; IV) the red wing [+30, +120] km s⁻¹; V) the reference far red wing [+120, +250] km s⁻¹. We do notexpect planetary signals in regions I and V, so they can be used to estimate the stability of the Lyman-α emission. The timestamps correspond to the phases in relation to the orbital motion of the planet.