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Anders Johansen. Profile picture.

Anders Johansen

Professor

Anders Johansen. Profile picture.

Slowing Down Type II Migration of Gas Giants to Match Observational Data

Author

  • Shigeru Ida
  • Hidekazu Tanaka
  • Anders Johansen
  • Kazuhiro D. Kanagawa
  • Takayuki Tanigawa

Summary, in English

The mass and semimajor axis distribution of gas giants in exoplanetary systems obtained by radial velocity surveys shows that super-Jupiter-mass planets are piled up at 1 au, while Jupiter/sub-Jupiter-mass planets are broadly distributed from ∼0.03 au to beyond 1 au. This feature has not been explained by theoretical predictions. In order to reconcile this inconsistency, we investigate evolution of gas giants with a new type II migration formula by Kanagawa et al., by comparing the migration, growth timescales of gas giants, and disk lifetime, and by population synthesis simulation. While the classical migration model assumes that a gas giant opens up a clear gap in the protoplanetary disk and the planet migration is tied to the disk gas accretion, recent high-resolution simulations show that the migration of gap-opening planets is decoupled from the disk gas accretion and Kanagawa et al. proposed that type II migration speed is nothing other than type I migration speed with the reduced disk gas surface density in the gap. We show that with this new formula, type II migration is significantly reduced for super-Jupiter-mass planets, if the disk accretion is driven by the disk wind as suggested by recent magnetohydrodynamic simulations. Population synthesis simulations show that super-Jupiter-mass planets remain at 1 au without any additional ingredient such as disk photoevaporation. Therefore, the mystery of the pile-up of gas giants at 1 au will be theoretically solved if the new formula is confirmed and wind-driven disk accretion dominates.

Department/s

  • Lund Observatory

Publishing year

2018

Language

English

Publication/Series

Astrophysical Journal

Volume

864

Issue

1

Document type

Journal article

Publisher

American Astronomical Society

Status

Published

ISBN/ISSN/Other

  • ISSN: 0004-637X