Recycling time and density of the gas inside the Hill sphere. The length unit is R_Hill. The velocity of the gas is measured in units of the Keplerian orbital velocity of the planet around the star. The recycling time is defined as the time the gas has already spent inside the Hill sphere. The arrows indicate the velocity of the gas. The density contour lines (cyan) are drawn at [2, 4, 8, 16] ρ₀. These lines are jagged because of the resolution of the grid. Left: xy plane or midplane. Middle: xz plane. Right: yz plane. The atmosphere is recycled up to the surface of the protoplanetary core. Gas around the z-axis has a lower recycling time than the gas in the midplane. This indicates that gas enters from the poles and leaves the atmosphere through the midplane.