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The growth of planets by pebble accretion in evolving protoplanetary discs

Bitsch, Bertram LU ; Lambrechts, Michiel LU and Johansen, Anders LU (2015) In Astronomy & Astrophysics 582.
Abstract
The formation of planets depends on the underlying protoplanetary disc structure, which in turn influences both the accretion and migration rates of embedded planets. The disc itself evolves on time scales of several Myr, during which both temperature and density profiles change as matter accretes onto the central star. Here we used a detailed model of an evolving disc to determine the growth of planets by pebble accretion and their migration through the disc. Cores that reach their pebble isolation mass accrete gas to finally form giant planets with extensive gas envelopes, while planets that do not reach pebble isolation mass are stranded as ice giants and ice planets containing only minor amounts of gas in their envelopes. Unlike... (More)
The formation of planets depends on the underlying protoplanetary disc structure, which in turn influences both the accretion and migration rates of embedded planets. The disc itself evolves on time scales of several Myr, during which both temperature and density profiles change as matter accretes onto the central star. Here we used a detailed model of an evolving disc to determine the growth of planets by pebble accretion and their migration through the disc. Cores that reach their pebble isolation mass accrete gas to finally form giant planets with extensive gas envelopes, while planets that do not reach pebble isolation mass are stranded as ice giants and ice planets containing only minor amounts of gas in their envelopes. Unlike earlier population synthesis models, our model works without any artificial reductions in migration speed and for protoplanetary discs with gas and dust column densities similar to those inferred from observations. We find that in our nominal disc model, the emergence of planetary embryos preferably should occur after approximately 2 Myr in order to not exclusively form gas giants, but also ice giants and smaller planets. The high pebble accretion rates ensure that critical core masses for gas accretion can be reached at all orbital distances. Gas giant planets nevertheless experience significant reduction in semi-major axes by migration. Considering instead planetesimal accretion for planetary growth, we show that formation time scales are too long to compete with the migration time scales and the dissipation time of the protoplanetary disc. All in all, we find that pebble accretion overcomes many of the challenges in the formation of ice and gas giants in evolving protoplanetary discs. (Less)
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author
organization
publishing date
type
Contribution to journal
publication status
published
subject
keywords
planets and satellites: formation, planet-disk interactions, protoplanetary disks, accretion disks, accretion
in
Astronomy & Astrophysics
volume
582
publisher
EDP Sciences
external identifiers
  • wos:000363538500112
  • scopus:84946113302
ISSN
0004-6361
DOI
10.1051/0004-6361/201526463
language
English
LU publication?
yes
id
47ed92a5-03ae-4f7b-8ed9-d75f7951a646 (old id 8383377)
date added to LUP
2015-12-18 14:20:18
date last changed
2017-11-19 04:00:52
@article{47ed92a5-03ae-4f7b-8ed9-d75f7951a646,
  abstract     = {The formation of planets depends on the underlying protoplanetary disc structure, which in turn influences both the accretion and migration rates of embedded planets. The disc itself evolves on time scales of several Myr, during which both temperature and density profiles change as matter accretes onto the central star. Here we used a detailed model of an evolving disc to determine the growth of planets by pebble accretion and their migration through the disc. Cores that reach their pebble isolation mass accrete gas to finally form giant planets with extensive gas envelopes, while planets that do not reach pebble isolation mass are stranded as ice giants and ice planets containing only minor amounts of gas in their envelopes. Unlike earlier population synthesis models, our model works without any artificial reductions in migration speed and for protoplanetary discs with gas and dust column densities similar to those inferred from observations. We find that in our nominal disc model, the emergence of planetary embryos preferably should occur after approximately 2 Myr in order to not exclusively form gas giants, but also ice giants and smaller planets. The high pebble accretion rates ensure that critical core masses for gas accretion can be reached at all orbital distances. Gas giant planets nevertheless experience significant reduction in semi-major axes by migration. Considering instead planetesimal accretion for planetary growth, we show that formation time scales are too long to compete with the migration time scales and the dissipation time of the protoplanetary disc. All in all, we find that pebble accretion overcomes many of the challenges in the formation of ice and gas giants in evolving protoplanetary discs.},
  articleno    = {A112},
  author       = {Bitsch, Bertram and Lambrechts, Michiel and Johansen, Anders},
  issn         = {0004-6361},
  keyword      = {planets and satellites: formation,planet-disk interactions,protoplanetary disks,accretion disks,accretion},
  language     = {eng},
  publisher    = {EDP Sciences},
  series       = {Astronomy & Astrophysics},
  title        = {The growth of planets by pebble accretion in evolving protoplanetary discs},
  url          = {http://dx.doi.org/10.1051/0004-6361/201526463},
  volume       = {582},
  year         = {2015},
}