Save the Planet, Feed the Star: How Super-Earths Survive Migration and Drive Disk Accretion

Abstract

Two longstanding problems in planet formation include (1) understanding how planets survive migration, and (2) articulating the process by which protoplanetary disks disperse---and in particular how they accrete onto their central stars. We can go a long way toward solving both problems if the disk gas surrounding planets has no intrinsic diffusivity ("viscosity"). In inviscid, laminar disks, a planet readily repels gas away from its orbit. On short timescales, zero viscosity gas accumulates inside a planet's orbit to slow Type I migration by orders of magnitude. On longer timescales, multiple super-Earths (distributed between, say, $\sim$0.1--10 AU) can torque inviscid gas out of interplanetary space, either inward to feed their stars, or outward to be blown away in a wind. We explore this picture with 2D hydrodynamics simulations of Earths and super-Earths embedded in inviscid disks, confirming their slow/stalled migration even under gas-rich conditions, and showing that disk transport rates range up to $\sim$$10^{-7}{M}_{\odot }\mathrm{y}{\mathrm{r}}^{-1}$ and scale as $\dot{M}\propto \Sigma M_{\mathrm{p}}^{3/2}$, where $\Sigma$ is the disk surface density and $M_{\mathrm{p}}$ is the planet mass. Gas initially sandwiched between two planets is torqued past both into the inner and outer disks. In sum, sufficiently compact systems of super-Earths can clear their natal disk gas, in a dispersal history that may be complicated and non-steady, but which conceivably leads over Myr timescales to large gas depletions similar to those characterizing transition disks.

Accepted to ApJ

References in corpus (16)

• Accretion Rates in Herbig Ae stars
• Make Super-Earths, Not Jupiters: Accreting Nebular Gas onto Solid Cores at 0.1 AU and Beyond
• Characterising the Gravitational Instability in Cooling Accretion Discs
• Why Do T Tauri Disks Accrete?
• Treating gravity in thin disk simulations
• What is the Mass of a Gap-Opening Planet?
• Type I Planet Migration in Nearly Laminar Disks
• Synthesizing Exoplanet Demographics from Radial Velocity and Microlensing Surveys, II: The Frequency of Planets Orbiting M Dwarfs
• On the gap-opening criterion of migrating planets in protoplanetary disks
• Protoplanetary Disks as (Possibly) Viscous Disks
• On the width and shape of the corotation region for low-mass planets
• The Sizes and Depletions of the Dust and Gas Cavities in the Transitional Disk J160421.7-213028
• Wind-driven Accretion in Transitional Protostellar Disks
• Type III migration in a low viscosity disc
• A gas density drop in the inner 6 AU of the transition disk around the Herbig Ae star HD 139614: Further evidence for a giant planet inside the disk?
• Planetary Torque in 3D Isentropic Disks

Cited by in corpus (36)

• Multiple Disk Gaps and Rings Generated by a Single Super-Earth
• Magnetospheric Truncation, Tidal Inspiral, and the Creation of Short and Ultra-Short Period Planets
• Multiple Disk Gaps and Rings Generated by a Single Super-Earth: II. Spacings, Depths, and Number of Gaps, with Application to Real Systems
• Homogeneous Analysis of the Dust Morphology of Transition Disks Observed with ALMA: Investigating dust trapping and the origin of the cavities
• An opening criterion for dust gaps in protoplanetary discs
• Inferring giant planets from ALMA millimeter continuum and line observations in (transition) disks
• Gas and multi-species dust dynamics in viscous protoplanetary discs: the importance of the dust back-reaction
• Migrating super-Earths in low-viscosity discs: unveiling the roles of feedback, vortices, and laminar accretion flows
• A Balanced Budget View on Forming Giant Planets by Pebble Accretion
• The End of Runaway: How Gap Opening Limits the Final Masses of Gas Giants
• Planet Formation: An Optimized Population-Synthesis Approach
• How do T Tauri stars accrete
• Migration of Jupiter mass planets in low viscosity discs
• Sub-Neptune Formation: The View from Resonant Planets
• PDS 70: A transition disk sculpted by a single planet
• Inner Super-Earths, Outer Gas Giants: How Pebble Isolation and Migration Feedback Keep Jupiters Cold
• Observing the linked depletion of dust and CO gas at 0.1-10 au in disks of intermediate-mass stars
• An ALMA survey of $\lambda$ Orionis disks: from supernovae to planet formation
• How Consumption and Repulsion Set Planetary Gap Depths and the Final Masses of Gas Giants
• Which planets trigger longer-lived vortices: low-mass or high-mass?
• Disk Accretion Driven by Spiral Shocks
• Cooling-Induced Vortex Decay in Keplerian Disks
• Dusty disc-planet interaction with dust-free simulations
• Deep and wide gaps by super Earths in low-viscosity discs
• Oscillatory migration of accreting protoplanets driven by a 3D distortion of the gas flow
• Trapping of Low-Mass Planets Outside the Truncated Inner Edges of Protoplanetary Discs
• Migrating Low-Mass Planets in Inviscid Dusty Protoplanetary Discs
• Planet-disc interaction in laminar and turbulent discs
• Planetary Migration in Protoplanetary Disks
• Migration of pairs of giant planets in low-viscosity discs
• Gap-opening Planets Make Dust Rings Wider
• Can Large-Scale Migration Explain the Giant Planet Occurrence Rate?
• Disk evolution and the fate of water
• Formation of Super-Earths by Tidally-Forced Turbulence
• Forming Gliese 876 Through Smooth Disk Migration
• Longterm Stability of Planetary Systems formed from a Transitional Disk