Delivery of gas onto the circumplanetary disk of giant planets: Planetary-mass dependence of the source region of accreting gas and mass accretion rate

TL;DR

This study uses high-resolution 3D hydrodynamic simulations to explore how planetary mass influences gas accretion onto circumplanetary disks, revealing different behaviors in low and high-mass regimes and providing semi-analytical formulas.

Contribution

It presents the first detailed analysis of planetary-mass dependence of gas accretion band width and rate using 3D simulations, extending previous 2D results.

Findings

Accretion band width scales as M_p^{1/6} for low-mass planets.

Mass accretion rate ratio onto CPD is approximately 0.4 across masses.

The mass dependence of 3D accretion rates matches previous 2D findings.

Abstract

Gas accretion onto the circumplanetary disks and the source region of accreting gas are important to reveal dust accretion that leads to satellite formation around giant planets. We performed local three-dimensional high-resolution hydrodynamic simulations of isothermal and inviscid gas flow around a planet to investigate planetary-mass dependence of gas accretion band width and gas accretion rate onto circumplanetary disks. We examined cases with various planetary masses corresponding to M_p=0.05-1M_{Jup} at 5.2 au, where M_{Jup} is the current Jovian mass. We found that the radial width of the gas accretion band is proportional to M_p^{1/6} for the low-mass regime with M_p < 0.2 M_{Jup} while it is proportional to M_p for the high-mass regime with M_p > 0.2M_{Jup}. We found that the ratio of the mass accretion rate onto the circumplanetary disk to that into the Hill sphere is about 0.4 regardless of planetary mass for the cases we examined. Combining our results with the gap model obtained from global hydrodynamic simulations, we derive semi-analytical formulae of mass accretion rate onto circumplanetary disks. We found that the mass dependence of our three-dimensional accretion rates is the same as the previously-obtained two-dimensional case, although the qualitative behavior of accretion flow onto the CPD is quite different between the two cases.