Formation of planetary systems by pebble accretion and migration: Hot super-Earth systems from breaking compact resonant chains

Andre Izidoro, Bertram Bitsch, Sean N. Raymond, Anders Johansen, Alessandro Morbidelli, Michiel Lambrechts, Seth A. Jacobson

Forskningsoutput: TidskriftsbidragArtikel i vetenskaplig tidskriftPeer review

6 Citeringar (SciVal)

Sammanfattning

At least 30% of main sequence stars host planets with sizes of between 1 and 4 Earth radii and orbital periods of less than 100 days.We use N-body simulations including a model for gas-assisted pebble accretion and disk–planet tidal interaction to study the formation of super-Earth systems.We show that the integrated pebble mass reservoir creates a bifurcation between hot super-Earths or hot-Neptunes (.15M) and super-massive planetary cores potentially able to become gas giant planets (&15M). Simulations with moderate pebble fluxes grow multiple super-Earth-mass planets that migrate inwards and pile up at the inner edge of the disk forming long resonant chains. We follow the long-term dynamical evolution of these systems and use the period ratio distribution of observed planet-pairs to constrain our model. Up to 95% of resonant chains become dynamically unstable after the gas disk dispersal, leading to a phase of late collisions that breaks the original resonant configurations. Our simulations naturally match observations when they produce a dominant fraction (&95%) of unstable systems with a sprinkling (.5%) of stable resonant chains (the Trappist-1 system represents one such example). Our results demonstrate that super-Earth systems are inherently multiple (N-2) and that the observed excess of single-planet transits is a consequence of the mutual inclinations excited by the planet–planet instability. In simulations in which planetary seeds are initially distributed in the inner and outer disk, close-in super-Earths are systematically ice rich. This contrasts with the interpretation that most super-Earths are rocky based on bulk-density measurements of super-Earths and photo-evaporation modeling of their bimodal radius distribution.We investigate the conditions needed to form rocky super-Earths. The formation of rocky super-Earths requires special circumstances, such as far more efficient planetesimal formation well inside the snow line, or much faster planetary growth by pebble accretion in the inner disk. Intriguingly, the necessary conditions to match the bulk of hot super-Earths are at odds with the conditions needed to match the Solar System.

Originalspråkengelska
ArtikelnummerA152
Antal sidor35
TidskriftAstronomy and Astrophysics
Volym650
DOI
StatusPublished - 2021 jun 1

Bibliografisk information

Funding Information:
A.I. thanks FAPESP for support via grants 16/19556-7 and 16/12686-2, and CNPq via process 313998/2018-3. Most simulations of this work were performed on the computer cluster at UNESP/FEG acquired with resources from FAPESP. S.N.R and A.M. thank the Agence Nationale pour la Recherche for support via grant ANR-13-BS05-0003- 01 (project MOJO). B.B., thanks the European Research Council (ERC Starting Grant 757 448-PAMDORA) for their financial support. A.J. was supported by the European Research Council under ERC Consolidator Grant agreement 724687-PLANETESYS, the Swedish Research Council (grant 2014-5775), and the Knut and Alice Wallenberg Foundation (grants 2012.0150, 2014.0017, and 2014.0048). Computer time for this study was also provided by the computing facilities MCIA (M?socentre de Calcul Intensif Aquitain) of the Universit? de Bordeaux and of the Universit? de Pau et des Pays de l?Adour. This research has made use of the NASA Exoplanet Archive, which is operated by the California Institute of Technology, under contract with the National Aeronautics and Space Administration under the Exoplanet Exploration Program.

Funding Information:
cA knowledgements. A.I. thanks FAPESP for support via grants 16/19556-7 and 16/12686-2, and CNPq via process 313998/2018-3. Most simulations of this work were performed on the computer cluster at UNESP/FEG acquired with resources from FAPESP. S.N.R and A.M. thank the Agence Nationale pour la Recherche for support via grant ANR-13-BS05-0003-01 (project MOJO). B.B., thanks the European Research Council (ERC Starting Grant 757 448-PAMDORA) for their financial support. A.J. was supported by the European Research Council under ERC Consolidator Grant agreement 724687-PLANETESYS, the Swedish Research Council (grant 2014-5775), and the Knut and Alice Wallenberg Foundation (grants 2012.0150, 2014.0017, and 2014.0048). Computer time for this study was also provided by the computing facilities MCIA (Mésocentre de Cal-cul Intensif Aquitain) of the Université de Bordeaux and of the Université de Pau et des Pays de l’Adour. This research has made use of the NASA Exo-planet Archive, which is operated by the California Institute of Technology, under contract with the National Aeronautics and Space Administration under the Exoplanet Exploration Program.

Publisher Copyright:
© 2021 EDP Sciences. All rights reserved.

Copyright:
Copyright 2021 Elsevier B.V., All rights reserved.

Ämnesklassifikation (UKÄ)

  • Astronomi, astrofysik och kosmologi

Fingeravtryck

Utforska forskningsämnen för ”Formation of planetary systems by pebble accretion and migration: Hot super-Earth systems from breaking compact resonant chains”. Tillsammans bildar de ett unikt fingeravtryck.

Citera det här