Evolution of the tracer fluid inserted into the Hill sphere of the M1 simulation after thermodynamic equilibrium was reached. At , the whole Hill sphere is filled with a uniform tracer fluid concentration of unity. Top panel: view of the midplane, middle panel: view of the front, and bottom panel: side view. The length unit used is R_Hill. The dashed cyan lines are iso-density lines at [2, 4, 8, 16, 32] ρ₀. The magenta circle is the atmospheric radius R_atm, defined such that inside R_atm, the azimuthal velocity is the largest component everywhere in the midplane, i.e., the gas rotates around the protoplanetary core. The atmosphere is elongated in the x-z view because of the stellar tidal forces.