The role of thermal feedback in the growth of planetary cores by pebble accretion in dust traps
File(s)
Published version
Author(s)
Cummins, Daniel P
Owen, James E
Type
Journal Article
Abstract
High-resolution millimetre-imaging of protoplanetary discs hasrevealed many containing rings and gaps. These rings can contain
large quantities of dust, often in excess of 10 M⊕, providing prime sites for efficient and rapid planet formation. Rapid planet
formation will produce high accretion luminosities, heating the surrounding disc. We investigate the importance of a planetary
embryo’s accretion luminosity by simulating the dynamics of the gas and dust in a dust ring, accounting for the energy liberated
as a resident planetary embryo accretes. The resulting heating alters the flow structure near the planet, increasing the accretion
rate of large, millimetre-to-centimetre-sized dust grains. We show how this process varies with the mass of dust in the ring and
the local background gas temperature, demonstrating that the thermal feedback always acts to increase the planet’s mass. This
increase in planet mass is driven primarily by the formation of vortices, created by a baroclinic instability once the accreting
planet heats the disc significantly outside its Hill radius. The vortices can then migrate with respect to the planet, resulting
in a complex interplay between planetary growth, gap-opening, dust trapping, and vortex dynamics. Planets formed within
dust traps can have masses that exceed the classical pebble isolation mass, potentially providing massive seeds for the future
formation of giant planets. Once pebble accretion ceases, the local dust size distribution is depleted in large grains, and much
of the remaining dust mass is trapped in the system’s L5 Lagrange point, providing potentially observable signatures of this
evolution.
large quantities of dust, often in excess of 10 M⊕, providing prime sites for efficient and rapid planet formation. Rapid planet
formation will produce high accretion luminosities, heating the surrounding disc. We investigate the importance of a planetary
embryo’s accretion luminosity by simulating the dynamics of the gas and dust in a dust ring, accounting for the energy liberated
as a resident planetary embryo accretes. The resulting heating alters the flow structure near the planet, increasing the accretion
rate of large, millimetre-to-centimetre-sized dust grains. We show how this process varies with the mass of dust in the ring and
the local background gas temperature, demonstrating that the thermal feedback always acts to increase the planet’s mass. This
increase in planet mass is driven primarily by the formation of vortices, created by a baroclinic instability once the accreting
planet heats the disc significantly outside its Hill radius. The vortices can then migrate with respect to the planet, resulting
in a complex interplay between planetary growth, gap-opening, dust trapping, and vortex dynamics. Planets formed within
dust traps can have masses that exceed the classical pebble isolation mass, potentially providing massive seeds for the future
formation of giant planets. Once pebble accretion ceases, the local dust size distribution is depleted in large grains, and much
of the remaining dust mass is trapped in the system’s L5 Lagrange point, providing potentially observable signatures of this
evolution.
Date Issued
2025-03-01
Date Acceptance
2025-01-07
Citation
Monthly Notices of the Royal Astronomical Society, 2025, 537 (4), pp.3603-3619
ISSN
0035-8711
Publisher
Oxford University Press
Start Page
3603
End Page
3619
Journal / Book Title
Monthly Notices of the Royal Astronomical Society
Volume
537
Issue
4
Copyright Statement
© 2025 The Author(s). Published by Oxford University Press on behalf of Royal Astronomical Society. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted reuse, distribution, and reproduction in any medium, provided the original work is properly cited.
License URL
Sponsor
The Royal Society
The Royal Society
The Royal Society
The Royal Society
Commission of the European Communities
Identifier
https://doi.org/10.1093/mnras/staf029
Grant Number
URF/R/211010
UF150412
RGF\EA\180207
RGF\EA\201038
853022
Subjects
accretion, accretion discs
ALMA
Astronomy & Astrophysics
GAP EDGES
GIANT PLANETS
Physical Sciences
planet-disc interactions
planets and satellites: formation
PRESSURE BUMPS
protoplanetary discs
PROTOPLANETARY DISK RINGS
ROSSBY-WAVE INSTABILITY
Science & Technology
SPECTRAL ENERGY-DISTRIBUTIONS
STREAMING INSTABILITY
SUBSTRUCTURES
VORTICES
Publication Status
Published
Date Publish Online
2025-01-09