The evolution of a circumplanetary disc with a dead zone

TL;DR

This study models circumplanetary discs with dead zones to assess their potential for forming Galilean satellites, finding insufficient material for in situ formation and suggesting external sources are needed.

Contribution

It introduces hydrodynamic simulations of dead zone circumplanetary discs, revealing their mass accumulation and limitations for satellite formation.

Findings

Dead zones lead to higher disc mass but similar temperature profiles.

Steady state discs with dead zones do not undergo accretion outbursts.

Disc mass is insufficient for in situ formation of Galilean satellites.

Abstract

We investigate whether the regular Galilean satellites could have formed in the dead zone of a circumplanetary disc. A dead zone is a region of weak turbulence in which the magnetorotational instability (MRI) is suppressed, potentially an ideal environment for satellite formation. With the grid-based hydrodynamic code, FARGO3D, we examine the evolution of a circumplanetary disc model with a dead zone. Material accumulates in the dead zone of the disc leading to a higher total mass and but a similar temperature profile compared to a fully turbulent disc model. The tidal torque increases the rate of mass transport through the dead zone leading to a steady state disc with a dead zone that does not undergo accretion outbursts. We explore a range of disc, dead zone and mass inflow parameters and find that the maximum mass of the disc is around 0.001 MJ . Since the total solid mass of such a disc is much lower, we find that there is not sufficient material in the disc for in situ formation of the Galilean satellites and that external supplement is required.