Abstract
I review the basics of the disc instability model (DIM) for dwarf novae and
soft-X-ray transients and its most recent developments, as well as the current
limitations of the model, focusing on the dwarf nova case. Although the DIM
uses the Shakura-Sunyaev prescription for angular momentum transport, which we
know now to be at best inaccurate, it is surprisingly efficient in reproducing
the outbursts of dwarf novae and soft X-ray transients, provided that some
ingredients, such as irradiation of the accretion disc and of the donor star,
mass transfer variations, truncation of the inner disc, etc., are added to the
basic model. As recently realized, taking into account the existence of winds
and outflows and of the torque they exert on the accretion disc may
significantly impact the model. I also discuss the origin of the superoutbursts
that are probably due to a combination of variations of the mass transfer rate
and of a tidal instability. I finally mention a number of unsolved problems and
caveats, among which the most embarrassing one is the modelling of the low
state. Despite significant progresses in the past few years both on our
understanding of angular momentum transport, the DIM is still needed for
understanding transient systems.
Description
A review of the disc instability model for dwarf novae, soft X-ray transients and related objects
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