2001/01/28 by Charles F. Gammie · 39 citations
Physics and Astronomy · #Accretion (finance) #Angular momentum #Astronomy and Astrophysical Research #Astrophysical Phenomena and Observations #Astrophysics and Star Formation Studies #Dimensionless quantity #Dissipation #Instability #Momentum (technical analysis) #Nonlinear system #Planet #Turbulence #astro-ph
paper · pdf · doi:10.1086/320631
published as Astrophys.J. 597 (2003) 131-141 · 16 pages, 11 figures, aastex 5.0, to appear in ApJ
arxiv created 2001/01/28 · openalex publication_date 2001/05/20 · arxiv updated 2009/12/01 · openalex created_date 2016/06/24 · openalex updated_date 2026/08/05
Thin, Keplerian accretion disks generically become gravitationally unstable at large radii. I investigate the nonlinear outcome of such instability in cool disks using razor-thin, local, numerical models. Cooling, characterized by a constant cooling time τ c , drives the instability. I show analytically that if the disk can reach a steady state in which heating by dissipation of turbulence balances cooling, then the dimensionless angular momentum flux density α = -1 . Numerical experiments show that (1) if τ c ≳ 3Ω -1 then the disk reaches a steady, gravitoturbulent state in which Q ~ 1 and cooling is balanced by heating due to dissipation of turbulence; (2) if τ c ≲ 3Ω -1 , then the disk fragments, possibly forming planets or stars; (3) in a steady, gravitoturbulent state, surface density structures have a characteristic physical scale ~64 G Σ/Ω 2 that is independent of the size of the computational domain.