Gas Flow across Gaps in Protoplanetary Disks

We analyze the gas accretion flow through a planet-produced gap in aprotoplanetary disk. We adopt the alpha disk model and ignore effects ofplanetary migration. We develop a semi-analytic, one-dimensional model thataccounts for the effects of the planet as a mass sink and also carry outtwo-dimensional hydrodynamical simulations of a planet embedded in a disk. Thepredictions of the mass flow rate through the gap based on the semi-analyticmodel generally agree with the hydrodynamical simulations at the 25% level.Through these models, we are able to explore steady state disk structures andover large spatial ranges. The presence of an accreting Jupiter-mass planetsignificantly lowers the density of the disk within a region of several timesthe planet's orbital radius. The mass flow rate across the gap (and onto thecentral star) is typically 10% to 25% of the mass accretion rate outside theorbit of the planet, for planet-to-star mass ratios that range from 5e-5 to1e-3.Comment: 10 pages, 3 figures, 1 table. To appear in The Astrophysical Journa