Steven Rendon-Restreppo -- Self-gravity processes in protoplanetary disks

Title: Self-gravity processes in protoplanetary disks

Abstract: 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 mea-
sure 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 ad-
vancements 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 by 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.