Séminaire IPAG

Self-gravity processes in protoplanetary disks

jeudi 21 mars 2024 - 11h00
Steven Rendon Restrepo - Leibniz Institute for Astrophysics in Potsdam (AIP)
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A key puzzle in Protoplanetary disks (PPDs) involves understanding the ori- gin of accretion, which stems from turbulence generated by various instabilities such as ideal/non-ideal MRI or vertical shear instability, among others. Dust embedded in this turbulent gaseous environment is an ideal candidate to measure indirectly the vertical stirring. However, measurements of dust scale height indicate thin dust layers, implying low vertical stirring, which doesn’t align with the observed accretion rates. This inconsistency may arise from oversimplified assumptions in stratification models. While numerical advancements have addressed some aspects, further theoretical work is needed to understand the disentangled gravitational influence between gas and dust. In the first part of this talk, I will present my analytical and numerical findings regarding the vertical layering and accretion of a self-gravitating PPD, made of gas and dust. The Gravitational Instability (GI) is one of the dominant theories in planet formation, describing how the disk can fragment into clumps. These clumps tend to reach masses akin to brown dwarfs, making this model less suitable for explaining gas giants formation. However, most simulations were conducted in 2D and made use of a smoothing for the gravitational potential. It was shown that this prescription underestimates the short range interaction of the self-gravity force by up to 100 %, potentially quenching gravitational collapse or overestimating the mass of GI-formed objects. Consequently, the initial mass of GI-formed objects could be highly overestimated, as they behave as a hollow clump (form a gravitational point of view). In this second part of my talk, I will introduce the exact self-gravity kernel that should be used in 2D simulations and explore its implications to the GI paradigm of planet formation thanks to 2D global simulations.
Hôtes : Gaylor Wafflard

Salle Manuel Forestini, 414 rue de la piscine, 38400 Saint Martin d'Hères