Related papers: The convective Urca process
We describe the evolution of double degenerate binary systems, consisting of components obeying the zero temperature mass radius relationship for white dwarf stars, from the onset of mass transfer to one of several possible outcomes…
The final outcomes of accreting ONe white dwarfs (ONe WDs) have been studied for several decades, but there are still some issues not resolved. Recently, some studies suggested that the deflagration of oxygen would occur for accreting ONe…
Based on stellar evolution simulations, we demonstrate that rapidly accreting white dwarfs in close binary systems are an astrophysical site for the intermediate neutron-capture process. During recurrent and very strong He-shell flashes in…
The origin of large magnetic fields ($\gtrsim 10^6~\mathrm{G}$) in isolated white dwarfs is not clear. One possible explanation is that crystallization of the star's core drives compositional convection, which when combined with the star's…
The formation channels and predicted populations of double-white dwarfs (DWDs) are important because a subset will evolve to be gravitational-wave sources and/or progenitors of Type Ia supernovae. Given the observed population of…
We study mass ejection from accretion disks formed in the merger of a white dwarf with a neutron star or black hole. These disks are mostly radiatively-inefficient and support nuclear fusion reactions, with ensuing outflows and…
We have modelled the multicycle evolution of rapidly-accreting CO white dwarfs (RAWDs) with stable H burning intermittent with strong He-shell flashes on their surfaces for $0.7\leq M_\mathrm{RAWD}/M_\odot\leq 0.75$ and [Fe/H] ranging from…
The previous analysis of the convective Urca neutrino loss process in degenerate, convective, quasi-static, carbon-burning cores by Barkat and Wheeler omitted specific consideration of the role of the kinetic energy flux. The arguments of…
In the framework of the Chandrasekhar-mass deflagration model for Type Ia supernovae (SNe Ia), a persisting free parameter is the initial morphology of the flame front, which is linked to the ignition process in the progenitor white dwarf.…
Evolution of a supernova type Ia progenitor requires formation of a CO white dwarf, which implies a dependence on the C burning rate (CBR). It can also be affected by the recently identified possibility of C flame quenching by convective…
We describe a mechanism by which a failed deflagration of a Chandrasekhar-mass carbon-oxygen white dwarf can turn into a successful thermonuclear supernova explosion, without invoking an ad hoc high-density deflagration-detonation…
The hydrogen-rich envelopes accreted by white dwarf stars from their red dwarf companions lead to thermonuclear runaways observed as classical nova eruptions peaking at up to 1 Million solar luminosities. Virtually all nova progenitors are…
Rapid bursts at optical wavelengths have been reported for several accreting white dwarfs, where the optical luminosity can increase by up to a factor 30 in less than an hour fading on timescales of several hours, and where the energy…
We perform smoothed particle hydrodynamics (SPH) simulations for merging binary carbon-oxygen (CO) white dwarfs (WDs) with masses of $1.1$ and $1.0$ $M_\odot$, until the merger remnant reaches a dynamically steady state. Using these…
We study C/O white dwarfs with masses of 1.0 to 1.4 Msun accreting solar-composition material at very high accretion rates. We address the secular changes in the WDs, and in particular, the question whether accretion and the thermonuclear…
Double white dwarf (WD) merger process and their post-merger evolution are important in many fields of astronomy, such as supernovae, gamma-ray bursts, gravitational waves, etc. The evolutionary outcomes of double ultra-massive WD merger…
Cataclysmic Variables (CVs) are close binary star systems with one component an accreting white dwarf (WD) and the other a larger cooler star that fills its Roche Lobe. One consequence of the WDs accreting material, is the possibility that…
Nova explosions occur on the white dwarf component of a Cataclysmic Variable binary stellar system that is accreting matter lost by its companion. When sufficient material has been accreted by the white dwarf, a thermonuclear runaway occurs…
We present the results of a systematic numerical study of an alternative progenitor scenario to produce type Ia supernova explosions, which is not restricted to the ignition of a CO white dwarf near the Chandrasekhar mass. In this scenario,…
The observed sub-class of "superluminous" Type Ia supernovae lacks a convincing theoretical explanation. If the emission of such objects were powered exclusively by radioactive decay of 56Ni formed in the explosion, a progenitor mass close…