Numerical simulations of type I planetary migration in non-turbulent magnetized discs |
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| Authors: | Sébastien Fromang Caroline Terquem Richard P Nelson |
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| Institution: | Astronomy Unit, Queen Mary, University of London, Mile End Road, London E1 4NS;Institut d'Astrophysique de Paris, UMR7095 CNRS, UniversitéPierre &Marie Curie–Paris 6, 98bis boulevard Arago, 75014 Paris, France;UniversitéDenis Diderot–Paris 7, 2 Place Jussieu, 75251 Paris Cedex 5, France;Institut Universitaire de France |
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| Abstract: | Using 2D magnetohydrodynamic (MHD) numerical simulations performed with two different finite-difference Eulerian codes, we analyse the effect that a toroidal magnetic field has on low-mass planet migration in non-turbulent protoplanetary discs. The presence of the magnetic field modifies the waves that can propagate in the disc. In agreement with a recent linear analysis, we find that two magnetic resonances develop on both sides of the planet orbit, which contribute to a significant global torque. In order to measure the torque exerted by the disc on the planet, we perform simulations in which the latter is either fixed on a circular orbit or allowed to migrate. For a  planet, when the ratio β between the square of the sound speed and that of the Alfven speed at the location of the planet is equal to 2, we find inward migration when the magnetic field B φ is uniform in the disc, reduced migration when B φ decreases as r ?1 and outward migration when B φ decreases as r ?2 . These results are in agreement with predictions from the linear analysis. Taken as a whole, our results confirm that even a subthermal stable field can stop inward migration of an earth-like planet. |
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| Keywords: | accretion accretion discs MHD waves methods: numerical planetary systems: protoplanetary discs |
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