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The evolution of white dwarfs is a simple gravothermal process. This process can be tested in two ways, through the luminosity function of these stars and through the secular variation of the period of pulsation of those stars that are…

Solar and Stellar Astrophysics · Physics 2013-04-30 J. Isern , S. Catalan , E. Garcia--Berro , M. Salaris , S. Torres

The prediction of the spins of the compact remnants is a fundamental goal of the theory of stellar evolution. Here, we confront the predictions for white dwarf spins from evolutionary models including rotation with observational…

Astrophysics · Physics 2009-11-13 M. P. L. Suijs , N. Langer , A. -J. Poelarends , S. -C. Yoon , A. Heger , F. Herwig

We study the thermodynamics of helium at densities relevant for white dwarf physics. We find evidence that, as the temperature is increased, there is first a first order transition between two superconducting phases followed by a second…

High Energy Astrophysical Phenomena · Physics 2014-02-26 Paulo F. Bedaque , Evan Berkowitz , Srimoyee Sen

Novae are cataclysmic variable binary systems in which a white dwarf primary is accreting material from a low mass companion. The importance of this accretion takes on added significance if the WD can increase its mass to reach the…

Solar and Stellar Astrophysics · Physics 2013-03-18 G. Newsham , S. Starrfield , F. Timmes

The origin of magnetic white dwarfs (MWDs) has been a long-standing puzzle. Proposed origin mechanisms have included: fossil fields frozen in from the progenitor convective core; a dynamo in the progenitor envelope; crystallization dynamos…

Solar and Stellar Astrophysics · Physics 2025-05-02 Ananya Mohapatra , Eric G. Blackman

Observations of galactic white dwarfs with Gaia have allowed for unprecedented modeling of white dwarf cooling, resolving core crystallization and sedimentary heating from neutron rich nuclei. These cooling sequences are sensitive to the…

Solar and Stellar Astrophysics · Physics 2021-07-07 M. E. Caplan , I. F. Freeman

We present an alternative interpretation of the nature of the extremely cool, high-velocity white dwarfs identified by Oppenheimer et al (2001) in a high-latitude astrometric survey. We argue that the velocity distribution of the majority…

Astrophysics · Physics 2009-11-06 I. Neill Reid , Kailash C. Sahu , Suzanne L. Hawley

Millisecond pulsars with white dwarf companions have typical eccentricities $e\sim 10^{-6}-10^{-3}$. The eccentricities of helium white dwarfs are explained well by applying the fluctuation-dissipation theorem to convective eddies in their…

Solar and Stellar Astrophysics · Physics 2024-09-23 Yair Cohen , Sivan Ginzburg , Maya Levy , Tal Bar Shalom , Yoav Siman Tov

White dwarfs experience a thermal renaissance when they receive mass from a stellar companion in a binary. For accretion rates < 10^-8 Msun/yr, the freshly accumulated hydrogen/helium envelope ignites in a thermally unstable manner that…

Astrophysics · Physics 2009-11-07 Dean M. Townsley , Lars Bildsten

Understanding the explosion mechanism of type Ia supernova is among the most challenging issues in astrophysics. Accretion of matter on a carbon-oxygen white dwarf from a companion star is one of the most important keys in this regard. Our…

Solar and Stellar Astrophysics · Physics 2023-05-10 Harish Kumar , Abhinav Gupta , Siddharth Savyasachi Malu , Shashikant Gupta

Thermohaline convection is a standard chemical mixing process in stellar interiors, yet its mixing efficiency is not fully settled. Competing theories predict turbulent diffusion coefficients, $D_\mu$, that can differ by orders of…

Solar and Stellar Astrophysics · Physics 2026-05-06 Valentin A. Skoutnev

We present new and improved evolutionary calculations for carbon-oxygen white dwarf (WD) stars appropriate for the study of massive ZZ Ceti stars. We follow the complete evolution of massive WD progenitors from the zero-age main sequence…

Astrophysics · Physics 2009-11-07 L. G. Althaus , A. M. Serenelli , A. H. Corsico , M. H. Montgomery

We present in this work new pulsational calculations for improved carbon-oxygen DA white dwarf models suitable for the study of massive ZZ Ceti stars. The background models employed in this study, presented in detail in a recent paper by…

Astrophysics · Physics 2009-11-10 A. H. Corsico , L. G. Althaus , M. H. Montgomery , E. Garcia-Berro , J. Isern

Rather than accreting via a disk, some White Dwarfs (WDs) in quiescent Dwarf Novae (DN) could accrete via an Advection-Dominated Accretion Flow (ADAF) possibly responsible for the X-ray Bremsstrahlung emission observed. Such a hot accretion…

Astrophysics · Physics 2009-10-31 Kristen Menou , Rosalba Perna , John Raymond

In this paper, four sets of evolutionary models are computed with different values of the mixing length parameter $\alpha_{\rm p}$ and the overshooting parameter $\delta_{\rm ov}$. The properties of the convective cores and the convective…

Solar and Stellar Astrophysics · Physics 2015-05-14 Jin Jie , Chunhua Zhu , Guoliang Lv

We study the effects of the sedimentation of the trace element 22Ne in the cooling of white dwarfs. In contrast with previous studies, which adopted a simplified treatment of the effects of 22Ne sedimentation, this is done self-consistently…

Astrophysics · Physics 2009-11-13 E. García--Berro , L. G. Althaus , A. H. Córsico , J. Isern

We have investigated the origin of a sub-class of carbon-polluted white dwarfs (DQ) originally identified as the ``hot DQ" white dwarfs. These objects are relatively hot (10 000 < T_eff < 25 000 K), have markedly higher carbon abundance…

Solar and Stellar Astrophysics · Physics 2023-03-01 Adela Kawka , Lilia Ferrario , Stephane Vennes

Convective overshoot mixing is a critical ingredient of stellar structure models, but is treated in most cases by ad hoc extensions of the mixing-length theory for convection. Advanced theories which are both more physical and numerically…

Solar and Stellar Astrophysics · Physics 2022-11-16 Felix Ahlborn , Friedrich Kupka , Achim Weiss , Martin Flaskamp

Hot white dwarfs with carbon-dominated atmospheres (hot DQs) are a cryptic class of white dwarfs. In addition to their deficiency of hydrogen and helium, most of these stars are highly magnetic, and a large fraction vary in luminosity. This…

Solar and Stellar Astrophysics · Physics 2016-01-21 Kurtis A. Williams , M. H. Montgomery , D. E. Winget , Ross E. Falcon , Michael Bierwagon

The surface gravities of cool (Teff < 13,000 K) hydrogen-atmosphere DA white dwarfs, determined from spectroscopic analyses, are found to be significantly higher than the canonical value of log g ~ 8 expected for these stars. It was…

Solar and Stellar Astrophysics · Physics 2015-05-28 P. -E. Tremblay , H. -G. Ludwig , M. Steffen , P. Bergeron , B. Freytag