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Related papers: Phase Separation in Ultramassive White Dwarfs

200 papers

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…

Astrophysics · Physics 2008-11-26 Vayujeet Gokhale , Xiao Meng Peng , Juhan Frank

We present new determinations of effective temperature, surface gravity, and masses for a sample of 46 hot DA white dwarfs selected from the EUVE and ROSAT Wide Field Camera bright source lists in the course of a near-IR survey for low mass…

Astrophysics · Physics 2009-10-31 Ralf Napiwotzki , Paul J. Green , Rex A. Saffer

We summarize masses and radii for a number of white dwarfs as deduced from a combination of proper motion studies, Hipparcos parallax distances, effective temperatures, and binary or spectroscopic masses. A puzzling feature of these data is…

Astrophysics · Physics 2009-11-11 G. J. Mathews , I. -S. Suh , B. O'Gorman , N. Q. Lan , W. Zech , K. Otsuki , F. Weber

Gravitational wave emission can lead to the coalescence of close pairs of compact objects orbiting each other. For the case of neutron stars such mergers may yield masses above the Tolman-Oppenheimer-Volkoff limit, leading to the formation…

Solar and Stellar Astrophysics · Physics 2019-06-06 V. V. Gvaramadze , G. Gräfener , N. Langer , O. V. Maryeva , A. Y. Kniazev , A. S. Moskvitin , O. I. Spiridonova

Clouds of high infrared extinction are promising sites of massive star/cluster formation. A large number of cloud cores discovered in recent years allows investigation of possible evolutionary sequence among cores in early phases. We have…

Astrophysics of Galaxies · Physics 2015-05-30 Huei-Ru Chen , Sheng-Yuan Liu , Yu-Nung Su , Mei-Yan Wang

A large fraction of white dwarf stars shows photospheric chemical composition polluted by heavy elements accreted from a debris disk. Such debris disks result from the tidal disruption of rocky planetesimals which had survived to whole…

Solar and Stellar Astrophysics · Physics 2017-04-26 F. C. Wachlin , G. Vauclair , S. Vauclair , L. G. Althaus

The rapid neutron-capture process (r-process) is a major process to synthesize elements heavier than iron, but the astrophysical site(s) of r-process is not identified yet. Neutron star mergers (NSMs) are suggested to be a major r-process…

Astrophysics of Galaxies · Physics 2015-11-20 Yutaka Hirai , Yuhri Ishimaru , Takayuki R. Saitoh , Michiko S. Fujii , Jun Hidaka , Toshitaka Kajino

The diffusion of elements is a key process in understanding the unusual surface composition of white dwarfs stars and their spectral evolution. The diffusion coefficients of Paquette et al. (1986) have been widely used to model diffusion in…

Solar and Stellar Astrophysics · Physics 2020-06-17 R. A. Heinonen , D. Saumon , J. Daligault , C. E. Starrett , S. D. Baalrud , G. Fontaine

White dwarfs (WDs) are the stellar core remnants of low mass stars. They are typically divided into three main composition groups: Oxygen Neon (ONe), Carbon Oxygen (CO) and Helium (He) WDs. The evolution of binary systems can significantly…

Solar and Stellar Astrophysics · Physics 2018-10-17 Yossef Zenati , Silvia Toonen , Hagai B. Perets

One possible fate of an accreting white dwarf is explosion in a type Ia supernova. However, the route to the thermonuclear runaway has always been uncertain owing to the lack of a convective model consistent with the Urca process. We derive…

Astrophysics · Physics 2016-08-30 P. Lesaffre , Ph. Podsiadlowski , C. A. Tout

We use multi-epoch spectroscopy of about 4000 white dwarfs in the Sloan Digital Sky Survey to constrain the properties of the Galactic population of binary white dwarf systems and calculate their merger rate. With a Monte Carlo code, we…

Solar and Stellar Astrophysics · Physics 2015-06-04 Carles Badenes , Dan Maoz

White dwarfs that have accreted planetary bodies are a powerful probe of the bulk composition of exoplanetary material. In this paper, we present a Bayesian model to explain the abundances observed in the atmospheres of 202 DZ white dwarfs…

Earth and Planetary Astrophysics · Physics 2021-03-31 John H. D. Harrison , Amy Bonsor , Mihkel Kama , Andrew M. Buchan , Simon Blouin , Detlev Koester

We present high precision, model independent, mass and radius measurements for 16 white dwarfs in detached eclipsing binaries and combine these with previously published data to test the theoretical white dwarf mass-radius relationship. We…

Polluted white dwarfs serve as astrophysical mass spectrometers - their photospheric abundances are used to infer the composition of planetary objects that accrete onto them. We show that due to asymmetries in the accretion process, the…

Earth and Planetary Astrophysics · Physics 2022-11-30 Marc G. Brouwers , Amy Bonsor , Uri Malamud

Electron captures by atomic nuclei in dense matter are among the most important processes governing the late evolution of stars, limiting in particular the stability of white dwarfs. Despite considerable progress in the determination of the…

Solar and Stellar Astrophysics · Physics 2023-04-05 N. Chamel , L. Perot , A. F. Fantina , D. Chatterjee , S. Ghosh , J. Novak , M. Oertel

In the standard Lambda cold dark matter paradigm, pure dark matter simulations predict dwarf galaxies should inhabit dark matter haloes with a centrally diverging density `cusp'. This is in conflict with observations that typically favour a…

We study the full evolution of a 1.313 Msun white dwarf star that descended from a 9 Msun main-sequence progenitor with an initial metallicity of Z=0.02. Using MESA r24.08.01, we calculate its entire evolution from pre-ZAMS to the WD…

Solar and Stellar Astrophysics · Physics 2026-03-12 Ana S. R. Antonini , Alejandra D. Romero , S. O. Kepler

This second paper presents an in-depth analysis of the composition of the planetary material that has been accreted onto seven white dwarfs with circumstellar dust and gas emission discs with abundances reported in Paper I. The white dwarfs…

Earth and Planetary Astrophysics · Physics 2024-06-18 L. K. Rogers , A. Bonsor , S. Xu , A. M. Buchan , P. Dufour , B. L. Klein , S. Hodgkin , M. Kissler-Patig , C. Melis , C. Walton , A. Weinberger

The creation of "hybrid" white dwarfs, made of a C-O core within a O-Ne shell has been proposed, and studies indicate that ignition in the C-rich central region makes these viable progenitors for thermonuclear (type Ia) supernovae. Recent…

High Energy Astrophysical Phenomena · Physics 2020-01-08 Carlyn N. Augustine , Donald E. Willcox , Jared Brooks , Dean M. Townsley , Alan C. Calder

We systematically explore the evolution of the merger of two carbon-oxygen (CO) white dwarfs. The dynamical evolution of a 0.9 Msun + 0.6 Msun CO white dwarf merger is followed by a three-dimensional SPH simulation. We use an elaborate…

Astrophysics · Physics 2019-08-19 Sung-Chul Yoon , Philipp Podsiadlowski , Stephan Rosswog