Related papers: Diffusion and the occurrence of hydrogen shell fla…
A 0.242 Msun object that finally becomes a helium white dwarf is evolved from Roche lobe detachment down to very low luminosities. In doing so, we employ our stellar code to which we have added a set of routines that compute the effects due…
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 calculated a grid of evolutionary models for white dwarfs with helium cores (He-WDs) and investigated the occurrence of hydrogen-shell flashes due to unstable hydrogen burning via CNO cycling. Our calculations show that such thermal…
We present a detailed calculation of the evolution of low-mass ($< 0.25~M_\odot $) helium white dwarfs. These white dwarfs (the optical companions to binary millisecond pulsars) are formed via long-term, low-mass binary evolution. After…
The present work is designed to explore the evolution of helium-core white dwarf (HeWD) stars for the case of metallicities much lower than the solar one (Z=0.001 and Z=0.0002). Evolution is followed in a self-consistent way with the…
We study the evolution of a system composed by a 1.4 \msun neutron star and a normal, solar composition star of 2 \msun in orbit with a period of 1 day. Calculations were performed employing the binary hydro code presented in Benvenuto & De…
We study the structure and evolution of white dwarf stars with helium-rich atmospheres (DB) in a self-consistent way with the predictions of time-dependent element diffusion. Our treatment of diffusion includes gravitational settling and…
We explore the effects of element diffusion due to gravitational settling and thermal and chemical diffusion on the pulsational properties of DA white dwarfs. To this end, we employ an updated evolutionary code coupled with a pulsational,…
Diffusion of elements in the atmosphere and envelope of a star can drastically alter its surface composition, leading to extreme chemical peculiarities. We consider the case of hot subdwarfs, where surface helium abundances range from…
Hydrogen-rich matter has been added to a CO white dwarf of initial mass 0.516 \msun at the rates $10^{-8}$ and $2\times 10^{-8}$ \msun \yrm1, and results are compared with those for a white dwarf of the same initial mass which accretes pure…
In the framework of our extensive modeling study of the spectral evolution of white dwarfs, we present here a new set of detailed calculations of the transport of residual hydrogen in helium-rich white dwarfs. First, we investigate the…
We present a grid of evolutionary tracks for low-mass white dwarfs with helium cores in the mass range from 0.179 to 0.414 Msol. The lower mass limit is well-suited for comparison with white dwarf companions of millisecond pulsars. The…
Element diffusion is a key physical process that substantially impacts the superficial abundances, internal structure, pulsation properties, and evolution of white dwarfs. We study the effect of Coulomb separation of ions in the cooling…
We present a set of full evolutionary sequences for white dwarfs with hydrogen-deficient atmospheres. We take into account the evolutionary history of the progenitor stars, all the relevant energy sources involved in the cooling, element…
Over 1500 DBZ or DZ white dwarfs (WDs) have been observed so far, and polluted atmospheres with metal elements have been found among these WDs. The surface heavy element abundances of known DBZ or DZ WDs show an evolutionary sequence. By…
Seismological observations with the Whole Earth Telescope (WET) allow the determination of the subsurface compositional structure of white dwarf stars. The hot DO PG 1159 has a helium surface layer with a mass of 0.001 Msun, while the…
A large number of low-mass (< 0.20 M_sun) helium white dwarfs (He WDs) have recently been discovered. The majority of these are orbiting another WD or a millisecond pulsar (MSP) in a close binary system; a few examples are found to show…
The present work is designed to explore the evolutionary and pulsational properties of low-mass white dwarfs with carbon/oxygen cores. In particular, we follow the evolution of a 0.33 Msun white dwarf remnant in a self-consistent way with…
The purpose of this work is to explore the evolution of helium-core white dwarf stars in a self-consistent way with the predictions of detailed non-gray model atmospheres and element diffusion. To this end, we consider helium-core white…
Motivated by the recent detection of single and binary He-core white dwarfs in metal-rich clusters, we present a full set of evolutionary calculations and colors appropriate for the study of such white dwarfs. The paper is also aimed at…