### Abstract

Thin, Keplerian accretion disks genetically 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 = [(9/4)γ(γ - 1)Ωτ_{c}]^{-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}1, then the disk fragments, possibly forming planets or stars; (3) in a steady, gravitoturbulent state, surface density structures have a characteristic physical scale ∼64GΣ/Ω^{2} that is independent of the size of the computational domain.

Original language | English (US) |
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Pages (from-to) | 174-183 |

Number of pages | 10 |

Journal | Astrophysical Journal |

Volume | 553 |

Issue number | 1 PART 1 |

DOIs | |

State | Published - May 20 2001 |

### Keywords

- Accretion, accretion disks
- Galaxies: Nuclei
- Solar system: Formation

### ASJC Scopus subject areas

- Astronomy and Astrophysics
- Space and Planetary Science

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## Cite this

*Astrophysical Journal*,

*553*(1 PART 1), 174-183. https://doi.org/10.1086/320631