Planet-disc interaction in laminar and turbulent discs

Stoll, Moritz H. R.; Picogna, Giovanni und Kley, Wilhelm (2017): Planet-disc interaction in laminar and turbulent discs. In: Astronomy & Astrophysics, Bd. 604, A28

Abstract

In weakly ionised discs turbulence can be generated through the vertical shear instability (VSI). Embedded planets are affected by a stochastic component in the torques acting on them, which can impact their migration. In this work we study the interplay between a growing planet embedded in a protoplanetary disc and the VSI turbulence. We performed a series of 3D hydrodynamical simulations for locally isothermal discs with embedded planets in the mass range from 5 to 100 Earth masses. We study planets embedded in an inviscid disc that is VSI unstable, becomes turbulent, and generates angular momentum transport with an effective alpha = 5 x 10(-4). This is compared to the corresponding viscous disc using exactly this alpha-value. In general we find that the planets have only a weak impact on the disc turbulence. Only for the largest planet (100 M-circle plus) does the turbulent activity become enhanced inside of the planet. The depth and width of a gap created by the more massive planets (30;100 M-circle plus) in the turbulent disc equal exactly that of the corresponding viscous case, leading to very similar torque strengths acting on the planet, with small stochastic fluctuations for the VSI disc. At the gap edges vortices are generated that are stronger and longer-lived in the VSI disc. Low mass planets (with M-p <= 10 M-circle plus) do not open gaps in the disc in either case, but generate for the turbulent disc an overdensity behind the planet that exerts a significant negative torque. This can boost the inward migration in VSI turbulent discs well above the Type I rate. Owing to the finite turbulence level in realistic 3D discs the gap depth will always be limited and migration will not stall in inviscid discs.

• Dokumententyp: Zeitschriftenartikel
• Fakultät: Physik
• Themengebiete: 500 Naturwissenschaften und Mathematik > 530 Physik
• ISSN: 1432-0746
• Sprache: Englisch