Cooling-regulated gas accretion onto gap-opening planets

Abstract

Gas accretion onto forming planets controls the final masses of giant planets and provides observable signatures of ongoing formation. How this process depends on poorly constrained. We present long-term, 3D global hydrodynamical simulations to quantify gas accretion onto gap-opening planets We systematically varied the cooling time, , and followed the evolution until a quasi-steady state was reached. id=R1 the cooling properties of this newly attracted gas remains id=R1 in the mass range between 1 and 3 Jupiter masses. id=R1 β, from near-isothermal (β=10^-2 in units of orbital time) to near-adiabatic (β=10^2) id=R1 Our simulations show that the gas accretion rate decreases monotonically with increasing β, as reaching values at β=10^2 that are approximately an order of magnitude lower than locally isothermal predictions, largely independent of planet mass. The reduction in accretion is traced to thermodynamic restructuring of the circumplanetary region: inefficient cooling weakens shocks and narrows the accretion bands feeding the circumplanetary disk. id=R4 dot M _ ̊m acc -0.18 , id=R2 Our results imply that thermodynamic effects should be accounted for when interpreting observed accretion rates of young planets and may introduce systematic uncertainties in commonly used locally isothermal assumptions.