Open AccessTesting the locality of transport in self‐gravitating accretion discs
Author(s) -
Lodato G.,
Rice W. K. M.
Publication year - 2004
Publication title -
monthly notices of the royal astronomical society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.058
H-Index - 383
eISSN - 1365-2966
pISSN - 0035-8711
DOI - 10.1111/j.1365-2966.2004.07811.x
Subject(s) - physics , smoothed particle hydrodynamics , parametrization (atmospheric modeling) , accretion (finance) , gravitation , rotational symmetry , dissipation , gravitational instability , cauchy stress tensor , astrophysics , viscous stress tensor , classical mechanics , mechanics , instability , radiative transfer , quantum mechanics , thermodynamics
In this paper, we examine the issue of characterizing the transport associated with gravitational instabilities in relatively cold discs, discussing in particular the conditions under which it can be described within a local, viscous framework. We present the results of global, three‐dimensional, smoothed particle hydrodynamics simulations of self‐gravitating accretion discs, in which the disc is cooled using a simple parametrization for the cooling function. Our simulations show that the disc settles in a ‘self‐regulated’ state, where the axisymmetric stability parameter Q ≈ 1 and where transport and energy dissipation are dominated by self‐gravity. We have computed the gravitational stress tensor and compared our results with expectations based on a local theory of transport. We find that, as long as the disc mass is smaller than 0.25 M ★ and the aspect ratio H / R ≲ 0.1 , transport is determined locally, thus allowing for a viscous treatment of the disc evolution.