Pebble Accretion and the Diversity of Planetary Systems

Abstract

I examine the standard model of planet formation, including pebble accretion, using numerical simulations. Planetary embryos large enough to become giant planets do not form beyond the ice line within a typical disk lifetime unless icy pebbles stick at higher speeds than in experiments using rocky pebbles. Systems like the Solar System (small inner planets, giant outer planets) can form if (i) icy pebbles are stickier than rocky pebbles, and (ii) the planetesimal formation efficiency increases with pebble size, which prevents the formation of massive terrestrial planets. Growth beyond the ice line is dominated by pebble accretion. Most growth occurs early, when the surface density of pebbles is high due to inward drift of pebbles from the outer disk. Growth is much slower after the outer disk is depleted. The outcome is sensitive to the disk radius and turbulence level, which control the lifetime and maximum size of pebbles. The outcome is sensitive to the size of the largest planetesimals since there is a threshold mass for the onset of pebble accretion. The planetesimal formation rate is unimportant provided that some large planetesimals form while pebbles remain abundant. Two outcomes are seen, depending on whether pebble accretion begins while pebbles are still abundant. Either (i) multiple gas giant planets form beyond the ice line, small planets form close to the star, and a Kuiper-belt-like disk of bodies is scattered outwards by the giant planets; or (ii) no giants form and bodies remain Earth-mass or smaller.

Accepted for publication in the Astrophysical Journal

References in corpus (18)

• Coagulation, fragmentation and radial motion of solid particles in protoplanetary disks
• Gas- and dust evolution in protoplanetary disks
• Particle Stirring in Turbulent Gas Disks: Including Orbital Oscillations
• Planet formation around stars of various masses: The snow line and the frequency of giant planets
• Closed-form expressions for particle relative velocities induced by turbulence
• Separating gas-giant and ice-giant planets by halting pebble accretion
• Towards planetesimals: dense chondrule clumps in the protoplanetary nebula
• The stickiness of micrometer-sized water-ice particles
• How to form planetesimals from mm-sized chondrules and chondrule aggregates
• Grain Retention and Formation of Planetesimals near the Snow Line in MRI-driven Turbulent Protoplanetary Disks
• Formation of Jupiter using opacities based on detailed grain physics
• Post-Oligarchic Evolution of Protoplanetary Embryos and the Stability of Planetary Systems
• The Migration of Gap-Opening Planets is not Locked to Viscous Disk Evolution
• Ice Lines, Planetesimal Composition and Solid Surface Density in the Solar Nebula
• Co-Accretion of Chondrules and Dust in the Solar Nebula
• Challenges in Forming the Solar System's Giant Planet Cores via Pebble Accretion
• On the filtering and processing of dust by planetesimals 1. Derivation of collision probabilities for non-drifting planetesimals
• Collisions of small ice particles under microgravity conditions

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