Thermal Instability of Advection-Dominated Disks against Local Perturbations

Publications of the Astronomical Society of Japan

Chen, Xingming¹  Kato, Shoji²  Abramowicz, Marek A.¹ 

[1] Department of Astronomy and Astrophysics, Göteborg University and Chalmers University of Technology, 412 96 Göteborg, Sweden;Department of Astronomy, Kyoto University, Sakyo-ku, Kyoto, 606-01

关键词: "Accretion;    accrection disks";    Instabilities;   

DOI  :  10.1093/pasj/48.1.67

学科分类：天文学(综合)

来源: Oxford University Press

【 摘 要 】

Thermalinstabilityisexaminedforadvection-dominatedone-temperatureaccretiondisks.Weconsideraxisymmetricperturbationswithshortwavelengthintheradialdirection.Theviscosityisassumedtobesufficientlysmallfortheverticalhydrostaticbalancetoholdinperturbedstates.Thetypeofviscosityisgiveneitherbytheα-viscosityorbyadiffusion-typestresstensor.Opticallythickdisksarefoundtobeingeneralmoreunstablethanopticallythinones.Whenthermaldiffusionispresent,opticallythindisksbecomestable,butopticallythickdisksarestillunstable.Theinstabilityoftheadvection-dominateddisksisdifferentfromthatofthegeometricallythindiskswithoutadvection.Inthecaseofnoadvection,thethermalmodebehavesundernoappreciablesurfacedensitychange.Inthecaseofadvection-dominateddisks,however,thethermalmodeoccurswithnoappreciablepressurechange(comparedwiththedensitychange),whenlocalperturbationsareconsidered.Thevariationsofangularmomentumandofthesurfacedensityassociatedwiththeperturbationsleadtoathermalinstability.Theastrophysicalimplicationsofthisinstabilityarebrieflydiscussed.

【 授权许可】

Unknown