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New solution to viscous evolution of accretion disks in binary systems

G. V. Lipunova·N. I. Shakura
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Abstract

Analytical investigation of time-dependent accretion in disks is carried out. We consider a time-dependent disk in a binary system at outburst which has a fixed tidally-truncated outer radius. The standard Shakura-Sunyaev model of the disk is considered. The vertical structure of the disk is accurately described in two regimes of opacity: Thomson and free-free. Fully analytical solutions are obtained, characterized by power-law variations of accretion rate with time. The solutions supply asymptotic description of disk evolution in flaring sources in the periods after outbursts while the disk is fully ionized. The X-ray flux of multicolor (black-body) alpha-disk is obtained as varying quasi-exponentially. Application to X-ray novae is briefly discussed concerning the observed faster-than-power decays of X-ray light curves. The case of time-dependent advective disk when the exponential variations of accretion rate can occur is discussed.

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G. V. Lipunova, N. I. Shakura. 2002-09-03. New solution to viscous evolution of accretion disks in binary systems. https://arxiv.org/abs/astro-ph/0103274

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