Data di Pubblicazione:
2004
Citazione:
Testing the locality of transport in self-gravitating accretion discs / G. Lodato, W.K.M. Rice. - In: MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY. - ISSN 0035-8711. - 351:2(2004), pp. 630-642. [10.1111/j.1365-2966.2004.07811.x]
Abstract:
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 Qapproximate to 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 0.25M(star) and the aspect ratio H/Rless than or similar to 0.1, transport is determined locally, thus allowing for a viscous treatment of the disc evolution.
Tipologia IRIS:
01 - Articolo su periodico
Keywords:
accretion, accretion discs; gravitation; instabilities; stars : formation; galaxies : active
Elenco autori:
G. Lodato, W.K.M. Rice
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