2009/06/08 by Zhaohuan Zhu, Lee Hartmann, Charles F. Gammie +2 · 178 citations
Chemistry · Physics and Astronomy · #Accretion (finance) #Astro and Planetary Science #Astronomy #Astrophysics #Astrophysics and Star Formation Studies #Convection #Instability #Magnetic field #Magnetohydrodynamics #Magnetorotational instability #Mechanics #Molecular Spectroscopy and Structure #Photosphere #Physics #Radiative transfer #Spectral line #Supersonic speed #Turbulence #astro-ph.SR
paper · pdf · doi:10.1088/0004-637x/701/1/620
published in The Astrophysical Journal 701(1), 620-634 (IOP Publishing) · Accepted by ApJ. Simulation movies can be downloaded at: http://www.astro.lsa.umich.edu/~zhuzh/research.html
arxiv created 2009/06/08 · openalex publication_date 2009/07/24 · arxiv updated 2011/02/11 · openalex created_date 2016/06/24 · openalex updated_date 2026/08/06
We have developed time-dependent models of FU Ori accretion outbursts to explore the physical properties of protostellar disks. Our two-dimensional, axisymmetric models incorporate full vertical structure with a new treatment of the radiative boundary condition for the disk photosphere. We find that FU Ori-type outbursts can be explained by a slow accumulation of matter due to gravitational instability. Eventually, this triggers the magnetorotational instability, which leads to rapid accretion. The thermal instability is triggered in the inner disk, but this instability is not necessary for the outburst. An accurate disk vertical structure, including convection, is important for understanding the outburst behavior. Large convective eddies develop at the transition region between the thermal instability high–low states in the inner disk. The models are in agreement with Spitzer IRS spectra and also with peak accretion rates and decay timescales of observed outbursts, though some objects show faster rise timescale. We also propose that convection may account for the observed mild-supersonic turbulence and the short-timescale variations of FU Orionis objects.