2002/11/28 by Hubert Klahr, Peter Bodenheimer · 9 citations
Chemical Engineering · Chemistry · Physics and Astronomy · #Advanced Combustion Engine Technologies #Astrophysics and Star Formation Studies #Molecular Spectroscopy and Structure #astro-ph
paper · pdf · doi:10.1086/344743
published as Astrophys.J. 582 (2003) 869-892 · 49 pages with 22 figures, Accepted for ApJ, January 2003 high res. figures at: http://www.mpia.de/homes/klahr
arxiv created 2002/11/28 · openalex publication_date 2003/01/10 · arxiv updated 2009/12/01 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/31
In this paper we present the global baroclinic instability as a source for vigorous turbulence leading to angular momentum transport in Keplerian accretion disks. We show by analytical considerations and three-dimensional radiation-hydrodynamic simulations that, in particular, protoplanetary disks have a negative radial entropy gradient, which makes them baroclinic. Two-dimensional numerical simulations show that a baroclinic flow is unstable and produces turbulence. These findings are tested for numerical effects by performing a simulation with a barotropic initial condition, which shows that imposed turbulence rapidly decays. The turbulence in baroclinic disks transports angular momentum outward and creates a radially inward-bound accretion of matter. Potential energy is released, and excess kinetic energy is dissipated. Finally, the reheating of the gas supports the radial entropy gradient, forming a self-consistent process. We measure accretion rates in our two-dimensional and three-dimensional simulations of = -10 -9 to -10 -7 M ☉ yr -1 and viscosity parameters of α = 10 -4 to 10 -2 , which fit perfectly together and agree reasonably with observations. The turbulence creates pressure waves, Rossby waves, and vortices in the ( R , ϕ)-plane of the disk. We demonstrate in a global simulation that these vortices tend to form out of little background noise and to be long-lasting features, which have already been suggested to lead to the formation of planets.