Speedie, J, Pudritz, RE, Cridland, AJ et al. (2 more authors) (2022) Turbulent disc viscosity and the bifurcation of planet formation histories. Monthly Notices of the Royal Astronomical Society, 510 (4). pp. 6059-6084. ISSN 0035-8711
Abstract
ALMA observations of dust ring/gap structures in a minority but growing sample of protoplanetary discs can be explained by the presence of planets at large disc radii – yet the origins of these planets remains debated. We perform planet formation simulations using a semi-analytic model of the HL Tau disc to follow the growth and migration of hundreds of planetary embryos initially distributed throughout the disc, assuming either a high or low turbulent α viscosity. We have discovered that there is a bifurcation in the migration history of forming planets as a consequence of varying the disc viscosity. In our high viscosity discs, inward migration prevails and yields compact planetary systems, tempered only by planet trapping at the water iceline around 5 au. In our lower viscosity models however, low mass planets can migrate outward to twice their initial orbital radii, driven by a radially extended region of strong outward-directed corotation torques located near the heat transition (where radiative heating of the disc by the star is comparable to viscous heating) – before eventually migrating inwards. We derive analytic expressions for the planet mass at which the corotation torque dominates, and find that this ‘corotation mass’ scales as Mp, corot ∼ α2/3. If disc winds dominate the corotation torque, the corotation mass scales linearly with wind strength. We propose that the observed bifurcation in disc demographics into a majority of compact dust discs and a minority of extended ring/gap systems is a consequence of a distribution of viscosity across the disc population.
Metadata
Item Type: | Article |
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Authors/Creators: |
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Copyright, Publisher and Additional Information: | © 2021 The Author(s) Published by Oxford University Press on behalf of Royal Astronomical Society. Reproduced in accordance with the publisher's self-archiving policy. |
Keywords: | planets and satellites: formation; planets and satellites: individual: HL Tau; planets and satellites: physical evolution; planet–disc interactions; protoplanetary discs |
Dates: |
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Institution: | The University of Leeds |
Academic Units: | The University of Leeds > Faculty of Engineering & Physical Sciences (Leeds) > School of Physics and Astronomy (Leeds) > Astrophysics (Leeds) |
Depositing User: | Symplectic Publications |
Date Deposited: | 30 Jun 2023 09:29 |
Last Modified: | 30 Jun 2023 09:29 |
Status: | Published |
Publisher: | Oxford University Press |
Identification Number: | 10.1093/mnras/stab3180 |
Open Archives Initiative ID (OAI ID): | oai:eprints.whiterose.ac.uk:201006 |