 Gas recycling through a planetary envelope

Gas recycling through a planetary envelope is exchange between gas near an embedded planetary embryo and the surrounding protoplanetary disk. Gas can enter and leave the embryo's gravitational neighbourhood instead of remaining in a permanently closed atmosphere. A geometrical region influenced by the embryo therefore need not contain a fixed collection of captured material.

The relevant comparison is between replacement and cooling. If new disk gas replenishes a region faster than it can lose energy, recycling can interfere with cooling-controlled planetary envelope growth. Three-dimensional hydrodynamic simulations demonstrated such connected inflow and outflow around low-mass embedded bodies.^[ref] The outcome depends on thermal structure and flow geometry; it is not a universal prohibition on gas capture by every core.