Related papers: Simulating the boundary layer between a white dwar…
Dwarf novae are a subset of cataclysmic variables that accrete material intermittently in short-duration outbursts with sometimes long quiescent intervals in between. During the quiescent state, the white dwarf (WD) photosphere may be…
We investigate the structure and evolution of a geometrically thin viscous Keplerian circumbinary (CB) disk, using detailed models of their radiative/convective vertical structure. We use a simplified description for the evolution of the…
Numerical simulations have shown that the often cited radiation pressure barrier to accretion onto massive stars can be circumvented, when the radiation field is highly anisotropic in the presence of a circumstellar accretion disk with high…
Our understanding of the structure and properties of accretion disks in quiescent Dwarf Novae and X-ray Transients is very limited. Observations during quiescence challenge some of the standard Disk Instability Model (DIM) predictions. Our…
Novae are the observational manifestations of thermonuclear runaways on the surface of accreting white dwarfs (WDs). Although novae are an ubiquitous phenomenon, their properties at low metallicity are not well understood. Using the…
We describe observational evidence for a new kind of interacting-binary-star outburst that involves both an accretion instability and an increase in thermonuclear shell burning on the surface of an accreting white dwarf. We refer to this…
We suggest that the low viscosity in close binary accretion disks during quiescence is due to magnetic fields from the companion star. In very late evolutionary phase the companion stars become brown dwarfs and have cooled down to such low…
In this paper we analyse the propagation of warps in protostellar circumbinary discs. We use these systems as a test environment in which to study warp propagation in the bending-wave regime, with the addition of an external torque due to…
We present high resolution Hubble Space Telescope ultraviolet spectroscopy of the dwarf nova EK TrA obtained in deep quiescence. The Space Telescope Imaging Spectrograph data reveal the broad Ly-alpha absorption profile typical of a…
White dwarfs, the final evolutionary stage of the vast majority of stars, serve as critical tools for cosmochronology, studies of planetary system evolution, and laboratories for non-standard physics, including exotic cooling channels and…
We collected F606W- and F814W-band time-series data of the Sagittarius low-reddening window in the Galactic bulge with the Advanced Camera far Surveys mounted on the Hubble Space Telescope. We sampled the region approximately every two…
In this paper, we revisit the problem of the determination of the frequency of occurrence of galactic nova outbursts which involve an oxygen-neon (ONe) white dwarf. The improvement with respect to previous work on the subject derives from…
Protostellar binaries harbour complex environment morphologies. Observations represent a snapshot in time, and projection and optical depth effects impair our ability to interpret them. Careful comparison with high-resolution models that…
Recent interpretations of narrow, variable absorption lines detected in some Type Ia supernovae suggest that their progenitors are surrounded by dense, circumstellar material. Similar variations detected in the symbiotic recurrent nova…
White dwarfs with metal-polluted atmospheres have been studied widely in the context of the accretion of rocky debris from evolved planetary systems. One open question is the geometry of accretion and how material arrives and mixes in the…
Classical novae are the results of surface thermonuclear explosions of H-rich material accreted by white dwarfs (WDs) from their low-mass main-sequence or red-giant binary companions. Chemical composition analysis of their ejecta shows that…
Asteroid material is detected in white dwarfs (WDs) as atmospheric pollution by metals, in the form of gas/dust discs, or in photometric transits. Within the current paradigm, minor bodies need to be scattered, most likely by planets, into…
We perform MHD simulations of a thin resistive and viscous accretion disk around a neutron star with the surface dipolar magnetic field of 10$^8$ Gauss. The system evolution is followed during the interval of 500 millisecond pulsar…
Interacting double white dwarf binaries can give rise to a wide variety of astrophysical outcomes ranging from faint thermonuclear and Type Ia supernovae to the formation of neutron stars and stably accreting AM Canum Venaticorum systems.…
The merger of compact binaries, especially black holes and neutron stars, is frequently invoked to explain gamma-ray bursts (GRB's). In this paper, we present three dimensional hydrodynamical simulations of the relatively neglected mergers…