The role of the drag force in the gravitational stability of dusty planet forming disc I. Analytical theory
Articolo
Data di Pubblicazione:
2023
Citazione:
The role of the drag force in the gravitational stability of dusty planet forming disc I. Analytical theory / C. Longarini, G. Lodato, G. Bertin, P. J Armitage. - In: MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY. - ISSN 1365-2966. - 519:2(2023 Feb), pp. 2017-2029. [10.1093/mnras/stac3653]
Abstract:
Recent observations show that planet formation is already underway in young systems, when the protostar is still embedded
into the molecular cloud and the accretion disc is massive. In such environments, the role of self-gravity (SG) and gravitational
instability (GI) is crucial in determining the dynamical evolution of the disc. In this work, we study the dynamical role of drag
force in self-gravitating discs as a way to form planetesimals in early protoplanetary stages. We obtain the dispersion relation for
density-wave perturbations on a fluid composed of two phases (gas and dust) interacting through the common gravitation field
and the mutual drag force, and we find that the stability threshold is determined by three parameters: the local dust-to-gas density
ratio, the dust relative temperature, and the relevant Stokes number. In a region of parameters space, where young protoplanetary
discs are likely to be found, the instability can be dust driven, occurring at small wavelengths. In this regime, the Jeans mass is
much smaller than the one predicted by the standard GI model. This mechanism can be a viable way to form planetary cores in
protostellar discs, since their predicted mass is about ∼10 M⊕.
Tipologia IRIS:
01 - Articolo su periodico
Keywords:
Hydrodynamics; Instabilities; Methods: analytical; Protoplanetary discs
Elenco autori:
C. Longarini, G. Lodato, G. Bertin, P. J Armitage
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