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Alexander Mustill. Profile picture.

Alexander Mustill

Researcher

Alexander Mustill. Profile picture.

Understanding the origin of white dwarf atmospheric pollution by dynamical simulations based on detected three-planet systems

Author

  • R. F. Maldonado
  • E. Villaver
  • A. J. Mustill
  • M. Chavez
  • E. Bertone

Summary, in English

Between 25 and 50 per cent of white dwarfs (WD) present atmospheric pollution by metals, mainly by rocky material, which has been detected as gas/dust discs, or in the form of photometric transits in some WDs. Planets might be responsible for scattering minor bodies that can reach stargazing orbits, where the tidal forces of the WD can disrupt them and enhance the chances of debris to fall on to the WD surface. The planet-planet scattering process can be triggered by the stellar mass-loss during the post main-sequence (MS) evolution of planetary systems. In this work, we continue the exploration of the dynamical instabilities that can lead to WD pollution. In a previous work, we explored two-planet systems found around MS stars and here we extend the study to three-planet system architectures. We evolved 135 detected three-planet systems orbiting MS stars to the WD phase by scaling their orbital architectures in a way that their dynamical properties are preserved using the N-body integrator package mercury. We find that 100 simulations (8.6 per cent) are dynamically active (having planet losses, orbit crossing, and scattering) on the WD phase, where low-mass planets (1-100 M⊕) tend to have instabilities in Gyr time-scales, while high-mass planets (>100 M⊕) decrease the dynamical events more rapidly as the WD ages. Besides, 19 simulations (1.6 $ per cent) were found to have planets crossing the Roche radius of the WD, where 9 of them had planet-star collisions. Our three-planet simulations have a slight increase in percentage of simulations that may contribute to the WD pollution than the previous study involving two-planet systems and have shown that planet-planet scattering is responsible of sending planets close to the WD, where they may collide directly to the WD, become tidally disrupted or circularize their orbits, hence producing pollution on the WD atmosphere.

Department/s

  • Lund Observatory

Publishing year

2020

Language

English

Pages

1854-1869

Publication/Series

Monthly Notices of the Royal Astronomical Society

Volume

499

Issue

2

Document type

Journal article

Publisher

Oxford University Press

Topic

  • Astronomy, Astrophysics and Cosmology

Keywords

  • circumstellar matter
  • Kuiper belt: general
  • planetary systems
  • planets and satellites: dynamical evolution and stability
  • stars: AGB and post-AGB
  • white dwarfs

Status

Published

Project

  • A unified picture of white dwarf planetary systems
  • IMPACT: Comets, asteroids and the habitability of planets

ISBN/ISSN/Other

  • ISSN: 0035-8711