Related papers: Fast and Slow Crystallization-driven Convection in…
We present a study of the hypothesis that white dwarfs undergo a spectral change from hydrogen- to helium-dominated atmospheres using a volume-limited photometric sample drawn from the $Gaia$ DR2 catalogue, the Sloan Digital Sky Survey…
We investigate the spectral evolution of white dwarfs by considering the effects of hydrogen mass in the atmosphere and convective overshooting above the convection zone. We notice the importance of the convective overshooting and suggest…
We present detailed evolutionary calculations for carbon - oxygen - and helium - core white dwarf (WD) models with masses ranging from M= 0.1 to M= 1.2 solar masses and for metallicities Z= 0.001 and Z= 0. The sequences cover a wide range…
We investigate whether the recently suggested rotation and crystallization driven dynamo can explain the apparent increase of magnetism in old metal polluted white dwarfs. We find that the effective temperature distribution of polluted…
We analyze stellar convection with the aid of 3D hydrodynamic simulations, introducing the turbulent cascade into our theoretical analysis. We devise closures of the Reynolds-decomposed mean field equations by simple physical modeling of…
We determine the phase diagram for dense carbon/ oxygen mixtures in White Dwarf (WD) star interiors using molecular dynamics simulations involving liquid and solid phases. Our phase diagram agrees well with predictions from Ogata et al. and…
Low-mass models of M-dwarfs that undergo the convective kissing instability fluctuate in luminosity and temperature resulting in a gap in the main sequence that is observed in the $Gaia$ data. During this instability, the models have…
We perform a calibration of the mixing length parameter at the bottom boundary of the convection zone for helium-dominated atmospheres of white dwarfs. This calibration is based on a grid of 3D DB (pure-helium) and DBA (helium-dominated…
(Abridged abstract) We explore the formation of ultra-massive (M_{\rm WD} \gtrsim 1.05 M_\sun$), carbon-oxygen core white dwarfs resulting from single stellar evolution. We also study their evolutionary and pulsational properties and…
We present full evolutionary calculations appropriate for the study of hydrogen-rich DA white dwarfs. This is done by evolving white dwarf progenitors from the zero age main sequence, through the core hydrogen burning phase, the helium…
A convective dynamo operating during the crystallization of white dwarfs is one of the promising channels to produce their observed strong magnetic fields. Although the magnitude of the fields generated by crystallization dynamos is…
We present here, for the first time, a 2D study of the overshoot convective mechanism in nova outbursts for a wide range of possible compositions of the layer underlying the accreted envelope. Previous surveys studied this mechanism only…
All single stars that are born with masses up to 8.5 - 10 $M_\odot$ will end their lives as a white dwarf (WD) star. In this evolutionary stage, WDs enter the cooling sequence, where the stars radiate away their thermal energy, and are…
The evolution of white dwarfs is essentially a gravothermal process of cooling in which the basic ingredients for predicting their evolution are well identified, although not always well understood. There are two independent ways to test…
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…
Novae are cataclysmic variables driven by accretion of H-rich material onto a white-dwarf (WD) star from its low-mass main-sequence binary companion. New time-domain observational capabilities, such as the Palomar Transient Factory and…
A large number of extremely low-mass helium white dwarfs (ELM WDs) have been discovered in recent years. The majority of them are found in close binary systems suggesting they are formed either through a common-envelope phase or via stable…
We examine the properties of white dwarfs (WDs) accreting hydrogen-rich matter in and near the stable burning regime of accretion rates as modeled by time-dependent calculations done with Modules for Experiments in Stellar Astrophysics…
Taking advantage of the Gaia Data Release 2, recent studies have revisited the evolution of carbon-polluted white dwarfs (DQs) across a large range of effective temperatures. These analyses have clearly confirmed the existence of two…
It was recently proposed that metal-rich white dwarfs (WDs) accrete their metals from compact debris disks found to exist around more than a dozen of them. At the same time, elemental abundances measured in atmospheres of some WDs imply…