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We follow the changes in the structure of the accretion disk of the dwarf nova V2051 Oph along two separate outbursts in order to investigate the causes of its recurrent outbursts. We apply eclipse mapping techniques to a set of light…

Astrophysics · Physics 2009-06-23 R. Baptista , R. F. Santos , M. Faundez-Abans , A. Bortoletto

A theoretical light curve for the 1999 outburst of U Scorpii is presented in order to obtain various physical parameters of the recurrent nova. Our U Sco model consists of a very massive white dwarf (WD) with an accretion disk and a…

Astrophysics · Physics 2009-10-31 Izumi Hachisu , Mariko Kato , Taichi Kato , Katsura Matsumoto

We present the results of local, vertically stratified, radiation MHD shearing box simulations of MRI turbulence appropriate for the hydrogen ionizing regime of dwarf nova and soft X-ray transient outbursts. We incorporate the…

High Energy Astrophysical Phenomena · Physics 2014-04-29 Shigenobu Hirose , Omer Blaes , Julian H. Krolik , Matthew S. B. Coleman , Takayoshi Sano

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…

Solar and Stellar Astrophysics · Physics 2020-08-05 Jean-Marie Hameury

We explore the origin of FUSE and HST STIS far UV spectra of the dwarf nova, EY Cyg, during its quiescence using \emph{combined} high gravity photosphere and accretion disk models as well as model accretion belts. The best-fitting single…

Astrophysics · Physics 2009-11-10 E. M. Sion , L. Winter , J. A. Urban , G. H. Tovmassian , S. Zharikov , B. T. Gaensicke , M. Orio

We show that accretion disks, both in the subcritical and supercritical accretion rate regime, may exhibit significant amplitude luminosity oscillations. The luminosity time behavior has been obtained by performing a set of time-dependent…

Astrophysics · Physics 2009-11-10 V. Teresi , D. Molteni , E. Toscano

We examine the AAVSO light curve of U Geminorum from 1908 to 2002, with particular focus on the October 1985 outburst. This outburst was longer than any other seen in U Gem by about a factor of 2, and appears to be unique among all dwarf…

Astrophysics · Physics 2009-11-07 John K. Cannizzo , Neil Gehrels , Janet A. Mattei

It is now widely accepted that most ultraluminous X-ray sources (ULXs) are binary systems whose large (above $10^{39}$ erg s$^{-1}$) apparent luminosities are explained by super-Eddington accretion onto a stellar-mass compact object. Many…

High Energy Astrophysical Phenomena · Physics 2020-11-25 Jean-Marie Hameury , Jean-Pierre Lasota

We present results from the Suzaku observations of the dwarf nova SS Cyg in quiescence and outburst in 2005 November. Owing to high sensitivity of the HXD PIN detector and high spectral resolution of the XIS, we have determined parameters…

Observations of tidal disruption events (TDEs) on a timescale of years after the main flare show evidence of continued activity in the form of optical/UV emission, quasi-periodic eruptions, and delayed radio flares. Motivated by this, we…

High Energy Astrophysical Phenomena · Physics 2025-04-09 Anthony L. Piro , Brenna Mockler

We have used FUSE to obtain thirteen observations of the dwarf nova VW Hyi covering the period from the end of a superoutburst through the following normal outburst of the system. Here, we present the quiescent spectra. They contain at…

Astrophysics of Galaxies · Physics 2010-01-15 Knox S. Long , Boris T. Gaensicke , Christian Knigge , Cynthia S. Froning , Berto Monard

AIMS: We present an analysis of an XMM-Newton observation of the dwarf novae V1504 Cyg during the decline from an outburst. Our goal is to search for evidence for an evaporated X-ray corona. Such a corona can be understood as an optically…

Solar and Stellar Astrophysics · Physics 2023-06-28 A. Dobrotka , J. -U. Ness , A. A. Nucita , M. Melicherčík

WZ Sge-type stars are an extreme subclass of dwarf novae characterised by very rare, large-amplitude superoutbursts. Within the disc instability model (DIM), such events are explained as being triggered by enhanced mass transfer from the…

Solar and Stellar Astrophysics · Physics 2026-02-26 Vitaly Neustroev , Paula Kvist , Miikka Siitonen , Veera Vuolteenaho

We have used HST/COS to obtain a series of 4 FUV (915-2148A) spectroscopic observations of the prototypical dwarf nova U Geminorum during its cooling following a two-week outburst. Our FUV spectral analysis of the data indicates that the…

Solar and Stellar Astrophysics · Physics 2017-12-13 Patrick Godon , Michael M. Shara , Edward M. Sion , David Zurek

We present 0.3 arcsec resolution observations of the disk around GM Aurigae with the Submillimeter Array (SMA) at a wavelength of 860 um and with the Plateau de Bure Interferometer at a wavelength of 1.3 mm. These observations probe the…

We present 120s cadence TESS observations of three superoutbursts of the SU UMa-type dwarf nova VW Hydri. Two events (SO2 in Sectors 87+88 and SO3 in Sector 93) exhibit a pronounced, temporally pronounced precursor-dip followed by a rapid…

Solar and Stellar Astrophysics · Physics 2026-02-11 Bisi Bernard Ogunwale , Shara Michael , Avi Shporer , Dafne Guetta , Lev Tal-Or

We discuss the multi-wavelength predictions of the two models proposed for SU UMa stars, i.e the enhanced mass transfer (EMT) and the tidal thermal instability (TTI) models. We focus on the systematic differences of the suggested scenarios…

Astrophysics · Physics 2009-11-10 Matthias R. Schreiber , Jean-Marie Hameury , Jean-Pierre Lasota

We construct time-dependent one-dimensional (vertically averaged) models of accretion disks produced by the tidal disruption of a white dwarf (WD) by a binary neutron star (NS) companion. Nuclear reactions in the disk midplane burn the WD…

High Energy Astrophysical Phenomena · Physics 2016-09-16 Ben Margalit , Brian D. Metzger

Many high-state cataclysmic variables (CVs) exhibit blue-shifted absorption features in their ultraviolet (UV) spectra -- a smoking-gun signature of outflows. However, the impact of these outflows on {\em optical} spectra remains much more…

Solar and Stellar Astrophysics · Physics 2024-06-21 Yusuke Tampo , Christian Knigge , Knox S. Long , James H. Matthews , Noel Castro Segura

We propose a new method to reconstruct the structure of accretion disks in dwarf novae using multi-band light curves of early superhumps. Our model assumes that early superhumps are caused by the rotation effect of non-axisymmetrically…

Astrophysics of Galaxies · Physics 2015-06-04 M. Uemura , T. Kato , T. Ohshima , H. Maehara