Are the observed gaps in protoplanetary discs caused by growing planets?

Abstract

Recent detailed observations of protoplanetary discs revealed a lot of sub-structures which are mostly ring-like. One interpretation is that these rings are caused by growing planets. These potential planets are not yet opening very deep gaps in their discs. These planets instead form small gaps in the discs to generate small pressure bumps exterior to their orbits that stop the inflow of the largest dust particles. In the pebble accretion paradigm, this planetary mass corresponds to the pebble isolation mass, where pebble accretion stops and efficient gas accretion starts. We perform planet population synthesis via pebble and gas accretion including type-I and type-II migration. In the first stage of our simulations, we investigate the conditions necessary for planets to reach the pebble isolation mass and compare their position to the observed gaps. We find that in order to match the gap structures 2000 M E in pebbles is needed, which would be only available for the most metal rich stars. We then follow the evolution of these planets for a few My to compare the resulting population with the observed exoplanet populations. Planet formation in discs with these large amounts of pebbles result in mostly forming gas giants and only very little super-Earths, contradicting observations. This leads to the conclusions that either (i) the observed discs are exceptions, (ii) not all gaps in observed discs are caused by planets or (iii) that we miss some important ingredients in planet formation related to gas accretion and/or planet migration.

9 pages, accepted for publication in MNRAS

References in corpus (22)

• One or more bound planets per Milky Way star from microlensing observations
• Separating gas-giant and ice-giant planets by halting pebble accretion
• Ring shaped dust accumulation in transition disks
• Gaps, Rings, and Non-Axisymmetric Structures in Protoplanetary Disks - From Simulations to ALMA Observations
• Evidence of fast pebble growth near condensation fronts in the HL Tau protoplanetary disk
• Global simulations of protoplanetary disks with ohmic resistivity and ambipolar diffusion
• The structure of protoplanetary discs around evolving young stars
• Formation of planetary systems by pebble accretion and migration: How the radial pebble flux determines a terrestrial-planet or super-Earth growth mode
• Dust size distributions in coagulation/fragmentation equilibrium: Numerical solutions and analytical fits
• Evolution of Protoplanetary Discs with Magnetically Driven Disc Winds
• Dust flow in gas disks in the presence of embedded planets
• Formation of planetary systems by pebble accretion and migration: Growth of gas giants
• Protoplanetary disk rings and gaps across ages and luminosities
• ALMA hints at the presence of two companions in the disk around HD 100546
• Planet population synthesis driven by pebble accretion in cluster environments
• Microlensing Results Challenge the Core Accretion Runaway Growth Scenario for Gas Giants
• The opacity of grains in protoplanetary atmospheres
• Rocky super-Earths or waterworlds: the interplay of planet migration, pebble accretion and disc evolution
• Time evolution of snow regions and planet traps in an evolving protoplanetary disk
• Highly inclined and eccentric massive planets. II. Planet-planet interactions during the disc phase
• ALMA observations require slower Core Accretion runaway growth
• The imprint of X-ray photoevaporation of planet-forming discs on the orbital distribution of giant planets

Cited by in corpus (23)

• The Ophiuchus DIsc Survey Employing ALMA (ODISEA)-III: the evolution of substructures in massive discs at 3-5 au resolution
• Interpreting high spatial resolution line observations of planet-forming disks with gaps and rings -- The case of HD 163296
• Setting the Stage: Planet formation and Volatile Delivery
• Probing the impact of varied migration and gas accretion rates for the formation of giant planets in the pebble accretion scenario
• Resilience of Planetesimal Formation in Weakly-Reinforced Pressure Bumps
• TW Hya: an old protoplanetary disc revived by its planet
• Promoted Mass Growth of Multiple, Distant Giant Planets through Pebble Accretion and Planet-Planet Collision
• A recipe for orbital eccentricity damping in the type-I regime for low viscosity 2D-discs
• Formation of wide-orbit giant planets in protoplanetary disks with a decreasing pebble flux
• Planetary core formation via multi-species pebble accretion
• Planet population synthesis: The role of stellar encounters
• ALMA constraints on assembly of Core Accretion planets
• Characterizing fragmentation and sub-Jovian clump properties in magnetized young protoplanetary disks
• The imprint of X-ray photoevaporation of planet-forming discs on the orbital distribution of giant planets -- II. Theoretical predictions
• Do all gaps in protoplanetary discs host planets?
• Quantifying the Similarity of Planetary System Architectures
• Constraining giant planet formation with synthetic ALMA images of the Solar System's natal protoplanetary disk
• The role of density perturbation on planet formation by pebble accretion
• How external photo-evaporation changes the chemical composition of the inner disc
• Emerging population of gap-opening planets around type-A stars -- Long-term evolution of the forming planets around HD 163296
• Hidden under a warm blanket: If planets existed in protostellar disks, they would hardly produce observable substructures
• Dust ring and gap formation by gas flow induced by low-mass planets embedded in protoplanetary disks $\mathrm{II}$. Time-dependent model
• The paradox of youth for ALMA planet candidates