The browser you are using is not supported by this website. All versions of Internet Explorer are no longer supported, either by us or Microsoft (read more here: https://www.microsoft.com/en-us/microsoft-365/windows/end-of-ie-support).

Please use a modern browser to fully experience our website, such as the newest versions of Edge, Chrome, Firefox or Safari etc.

Anders Johansen. Profile picture.

Anders Johansen

Professor

Anders Johansen. Profile picture.

A low accretion efficiency of planetesimals formed at planetary gap edges

Author

  • Linn E. J. Eriksson
  • Thomas Ronnet
  • Anders Johansen
  • Ravit Helled
  • Claudio Valletta
  • Antoine C. Petit

Summary, in English

Observations and models of giant planets indicate that such objects are enriched in heavy elements compared to solar abundances. The prevailing view is that giant planets accreted multiple Earth masses of heavy elements after the end of core formation. Such late solid enrichment is commonly explained by the accretion of planetesimals. Planetesimals are expected to form at the edges of planetary gaps, and here we address the question of whether these planetesimals can be accreted in large enough amounts to explain the inferred high heavy element contents of giant planets. We performed a series of N-body simulations of the dynamics of planetesimals and planets during the planetary growth phase, taking gas drag into account as well as the enhanced collision cross section caused by the extended envelopes. We considered the growth of Jupiter and Saturn via gas accretion after reaching the pebble isolation mass and we included their migration in an evolving disk. We find that the accretion efficiency of planetesimals formed at planetary gap edges is very low: less than 10% of the formed planetesimals are accreted even in the most favorable cases, which in our model corresponds to a few Earth masses. When planetesimals are assumed to form beyond the feeding zone of the planets, extending to a few Hill radii from a planet, accretion becomes negligible. Furthermore, we find that the accretion efficiency increases when the planetary migration distance is increased and that the efficiency does not increase when the planetesimal radii are decreased. Based on these results, we conclude that it is difficult to explain the large heavy element content of giant planets with planetesimal accretion during the gas accretion phase. Alternative processes most likely are required, such as accretion of vapor deposited by drifting pebbles.

Department/s

  • Lund Observatory
  • eSSENCE: The e-Science Collaboration

Publishing year

2022-05-01

Language

English

Publication/Series

Astronomy and Astrophysics

Volume

661

Document type

Journal article

Publisher

EDP Sciences

Topic

  • Astronomy, Astrophysics and Cosmology

Keywords

  • Planet-disk interactions
  • Planets and satellites: formation
  • Protoplanetary disks

Status

Published

ISBN/ISSN/Other

  • ISSN: 0004-6361