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Title: On the diversity of magnetic interactions in close-in star-planet systems

Magnetic interactions between close-in planets and their host star can play an important role in the secular orbital evolution of the planets, as well as the rotational evolution of their host. As long as the planet orbits inside the Alfvén surface of the stellar wind, the magnetic interaction between the star and the planet can modify the wind properties and also lead to direct angular momentum transfers between the two. We model these star-planet interactions using compressible magnetohydrodynamic (MHD) simulations, and quantify the angular momentum transfers between the star, the planet, and the stellar wind. We study the cases of magnetized and non-magnetized planets and vary the orbital radius inside the Alfvén surface of the stellar wind. Based on a grid of numerical simulations, we propose general scaling laws for the modification of the stellar wind torque, for the torque between the star and the planet, and for the planet migration associated with the star-planet magnetic interactions. We show that when the coronal magnetic field is large enough and the star is rotating sufficiently slowly, the effect of the magnetic star-planet interaction is comparable to tidal effects and can lead to a rapid orbital decay.
Authors:
 [1] ; ;  [2] ;  [3]
  1. Département de physique, Université de Montréal, C.P. 6128 Succ. Centre-Ville, Montréal, QC H3C-3J7 (Canada)
  2. Laboratoire AIM Paris-Saclay, CEA/Irfu Université Paris-Diderot CNRS/INSU, F-91191 Gif-sur-Yvette (France)
  3. Astrophysics group, School of Physics, University of Exeter, Stocker Road, Exeter EX4 4QL (United Kingdom)
Publication Date:
OSTI Identifier:
22370015
Resource Type:
Journal Article
Resource Relation:
Journal Name: Astrophysical Journal; Journal Volume: 795; Journal Issue: 1; Other Information: Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
79 ASTROPHYSICS, COSMOLOGY AND ASTRONOMY; ALFVEN WAVES; ANGULAR MOMENTUM TRANSFER; COMPUTERIZED SIMULATION; DECAY; INTERACTIONS; MAGNETIC FIELDS; MAGNETIC STARS; MAGNETOHYDRODYNAMICS; MIGRATION; ORBITS; PLANETS; SATELLITES; SCALING LAWS; STABILITY; STAR EVOLUTION; STELLAR WINDS; SURFACES; TORQUE