3D model of the upper atmosphere of WASP-107b simulated with the EVE code. Particles of metastable helium escape at the exobase (shown in projection as a dashed black circle), which separates the simulated thermosphere and exosphere. The planet as seen in the NIR continuum is shown as a black disc. The dotted blue line shows the projection of the Roche lobe. The green curve shows the orbit of WASP-107b. Top panel: view along the line of sight towards Earth, with metastable helium particles shown in grey. The yellow disc is the star. Bottom panel: view from above of the planetary system. Metastable helium particles are coloured as a function of their radial velocity and only shown within the orbital plane for the sake of clarity.