Size-selective accretion of dust on to CPDs: low CPD masses and filtration of larger grains

ABSTRACT The major satellites of Jupiter and Saturn are believed to have formed in circumplanetary discs (CPDs), which orbit forming giant protoplanets. Gas dust CPDs different distributions affect each other by drag, varies with grain size. Yet simulations multiple sizes separate dynamics not been done before. We seek assess how much size there is CPDs. run multifluid 3D hydrodynamical including gas four discrete from 1 μm mm, representing a continuous distribution. consider 1MJup protoplanet embedded protoplanetary disc around M⊙ star. Our results show truncated MRN (Mathis-Rumpl-Nordsieck) distribution at smaller sizes, starts tail off = 100 near zero mm. Large grains, hold most the mass, very inefficient accretion CPD, due filtration. Therefore, CPDs’ masses must be small, mass ratio ∼ few × 10−6 protoplanet. These corresponding millimetre opacities line CPD fluxes observed date.