Related papers: Dwarf Novae at Low Mass Transfer Rates
The outbursts of the dwarf nova WZ Sagittae occur on timescales which are much longer than expected from the standard thermal viscous disc instability model, which correctly reproduces the outburst behaviour of many other dwarf novae. In…
FO Aquarii, an asynchronous magnetic cataclysmic variable (intermediate polar) went into a low-state in 2016, from which it slowly and steadily recovered without showing dwarf nova outbursts. This requires explanation since in a low-state,…
Dwarf novae are white dwarfs accreting matter from a nearby red dwarf companion. Their regular outbursts are explained by a thermal-viscous instability in the accretion disc, described by the disc instability model that has since been…
We discuss two mechanisms that could result in an enhancement of the mass transfer rate during outbursts of dwarf novae and soft X-ray transients: the hot outer disc rim itself could heat the L1 point and scattered radiation by optically…
The self-sustained turbulence which develops in magnetized accretion disks is suppressed in the weakly-ionized, quiescent disks of close binary stars. Because accretion still proceeds during quiescence, another viscosity mechanism operates…
Dwarf novae are semi-detached binaries, where a white dwarf accretes material from a cool main-sequence companion via an accretion disk, and are known for their intermittent outbursts, making them key systems for studying accretion physics.…
The existing disk instability model for dwarf nova eruptions is reviewed, in the light of recent progress in the understanding of angular momentum transport in accretion disks. It is proposed that the standard lower branch in the…
Dwarf nova outbursts result from enhanced mass transport through the accretion disc of a cataclysmic variable system. We assess the question of whether these outbursts are caused by an enhanced mass transfer from the late-type main sequence…
Many black hole X-ray transients are in a low state for several decades until an outburst occurs. We interpret this outburst behaviour as a marginal occurrence of a dwarf nova type disk instability in the cool outer accretion disk. We…
We show that irradiation of the accretion disc by the white dwarf limits the occurrence of dwarf nova outbursts in post nova accretion discs. After the nova explosion, the white dwarf has to cool for up to ~100 yr - depending on the orbital…
We consider accretion discs in close binary systems. We show that heating of a disc at the impact point of the accretion stream contributes significantly to the local energy budget at its outer edge. As a result the thermal balance relation…
WZ Sge-type dwarf novae form one of the most intriguing classes of compact accreting binaries. They are recognized as the most evolved population of hydrogen-rich cataclysmic variables. Yet they exhibit energetic disk-powered outbursts with…
Using the disc instability model and a simple but physically reasonable model for the X-ray, extreme UV, UV and optical emission of dwarf novae we investigate the time lags observed between the rise to outburst at different wavelengths. We…
The disc instability model which is supposed to describe outbursts of dwarf nova and low-mass X-ray binary transient systems is presented and reviewed in detail. Various deficiencies of the model are pointed out and various remedies and…
The phenomenological Disc Instability Model has been successful in reproducing the observed light curves of dwarf nova outbursts by invoking an enhanced Shakura-Sunyaev $\alpha$ parameter $\sim0.1-0.2$ in outburst compared to a low value…
Dwarf novae (DNe) are accreting white dwarfs that show eruptions due to a thermal-viscous instability in the accretion disk. The outburst timescales constrain $\alpha$, the ratio of the viscous stress to the thermal pressure, and so the…
Dwarf Novae and low-mass X-ray binaries are eruptive binary systems comprised of a Roche-lobe overflowing solar-type star and an accreting compact object. Their recurrence time can be explained by a low-accreting phase, the quiescence,…
We report on our photometric observations of the 2016 superoutburst of ASASSN-16eg. This object showed a WZ Sge-type superoutburst with prominent early superhumps with a period of 0.075478(8) d and a post-superoutburst rebrightening. During…
The 2001 outburst of WZ Sagittae has shown the most compelling evidence yet for an enhancement of the mass transfer rate from the donor star during a dwarf nova outburst in the form of hot-spot brightening. I show that even in this extreme…
We have analysed a series of Suzaku data and one dataset of XMM-Newton of the SU UMa type dwarf nova VW Hyi in optical quiescence. The observed spectra in the 0.2-10 keV band are moderately well represented by multi-temperature thermal…