Open AccessLimit‐Cycle Behaviour of Thermally Unstable Accretion Flows on to Black Holes
Author(s) -
Szuszkiewicz Ewa,
Miller John C.
Publication year - 1998
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 - 10.1046/j.1365-8711.1998.01668.x
Subject(s) - physics , accretion (finance) , advection , instability , transonic , limit cycle , thermal instability , astrophysics , thermal , limit (mathematics) , mechanics , accretion disc , nonlinear system , thermodynamics , mathematical analysis , mathematics , quantum mechanics , aerodynamics
Non‐linear time‐dependent calculations are being carried out in order to study the evolution of vertically integrated models of non‐self‐gravitating, transonic accretion discs around black holes. In this paper we present results from a new calculation for a high‐α model similar to one studied previously by Honma, Matsumoto &38; Kato who found evidence for limit‐cycle behaviour connected with thermal instability. Our results are in substantial agreement with theirs but, in our calculation, the disc material does not always remain completely optically thick and we include a suitable treatment for this. We followed the evolution for several cycles and determined the period of the cycle as being about 780 s. Advective cooling is dominant in the region just behind the outward‐moving peak of surface density. The behaviour of this model is significantly different from what we saw earlier for low‐α models (which we discussed in a previous paper) and we contrast and compare the two situations.