Outbursts of irradiated accretion discs
journal contributionposted on 2019-10-02, 15:33 authored by A. R. King
I solve analytically the viscous evolution of an irradiated accretion disc, as seen during outbursts of soft X-ray transients. The solutions predict steep power-law X-ray decays LX ∼ (1 + t/tvisc)−4, changing to LX ∼ (1 − t/t′visc)4 at late times, where tvisc, t′visc are viscous time-scales. These forms closely resemble the approximate exponential and linear decays inferred by King and Ritter in these two regimes. The decays are much steeper than for unirradiated discs because the viscosity is a function of the central accretion rate rather than of local conditions in the disc.
I thank Hans Ritter, John Cannizzo and Henk Spruit for very helpful discussions, Graham Wynn for help with curve– fitting, and the U.K. Particle Physics and Astronomy Research Council for a Senior Fellowship. Theoretical astrophysics research at Leicester is supported by a PPARC Rolling Grant.
CitationMonthly Notices of the Royal Astronomical Society, 1998, 296 (4), pp. L45-L50 (6)
Author affiliation/Organisation/COLLEGE OF SCIENCE AND ENGINEERING/Department of Physics and Astronomy
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