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Related papers: Probing the core and envelope structure of DBV whi…

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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

Cooling white dwarfs (WDs) can yield accurate ages when theoretical cooling models fully account for the physics of the dense plasma of WD interiors. We use MESA to investigate cooling models for a set of massive and ultra-massive WDs…

Solar and Stellar Astrophysics · Physics 2020-10-21 Evan B. Bauer , Josiah Schwab , Lars Bildsten , Sihao Cheng

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…

Astrophysics · Physics 2009-11-06 A. M. Serenelli , L. G. Althaus , R. D. Rohrmann , O. G. Benvenuto

Recently a new particle physics model called Bound Dark Matter (BDM) has been proposed in which dark matter (DM) particles are massless above a threshold energy (Ec) and acquire mass below it due to nonperturbative methods. Therefore, the…

Cosmology and Nongalactic Astrophysics · Physics 2013-05-30 Jorge Mastache , Axel de la Macorra , Jorge L. Cervantes-Cota

We construct an effective field theory of a two-neutron halo nucleus in the limit where the two-neutron separation energy $B$ and the neutron-neutron two-body virtual energy $\epsilon_n$ are smaller than any other energy scale in the…

Nuclear Theory · Physics 2022-05-27 Masaru Hongo , Dam Thanh Son

Stellar evolution models of B-type stars are still uncertain in terms of internal mixing properties, notably in the area between the convective core and the radiative envelope. This impacts age determination of such stars in addition to the…

Solar and Stellar Astrophysics · Physics 2023-09-26 Mathias Michielsen , Timothy Van Reeth , Andrew Tkachenko , Conny Aerts

Asteroseismology of non-radial pulsations in Hot B Subdwarfs (sdB stars) offers a unique view into the interior of core-helium-burning stars. Ground-based and space-borne high precision light curves allow for the analysis of pressure and…

Solar and Stellar Astrophysics · Physics 2017-11-08 J. -T. Schindler , Elizabeth M. Green , W. David Arnett

We present the first grid of 3D simulations for the pure-helium atmospheres of DB white dwarfs. The simulations were computed with the CO5BOLD radiation-hydrodynamics code and cover effective temperatures and surface gravities between 12000…

Solar and Stellar Astrophysics · Physics 2018-09-05 E. Cukanovaite , P. -E. Tremblay , B. Freytag , H. -G. Ludwig , P. Bergeron

All the neutron star (NS) atmosphere models published so far have been calculated in the "cold plasma approximation", which neglects the relativistic effects in the radiative processes, such as cyclotron emission/absorption at harmonics of…

High Energy Astrophysical Phenomena · Physics 2015-06-03 V. F. Suleimanov , G. G. Pavlov , K. Werner

A photometric and spectroscopic analysis of 152 cool white dwarf stars is presented. The discovery of 7 new DA white dwarfs, 2 new DQ white dwarfs, 1 new magnetic white dwarf, and 3 weak magnetic white dwarf candidates, is reported, as well…

Astrophysics · Physics 2009-10-31 P. Bergeron , S. K. Leggett , Maria Teresa Ruiz

The recent discovery and characterization of the diversity of the atmospheres of exoplanets and brown dwarfs calls for the development of fast and accurate analytical models. We quantify the accuracy of the analytical solution derived in…

Earth and Planetary Astrophysics · Physics 2015-01-21 Vivien Parmentier , Tristan Guillot , Jonathan J. Fortney , Mark S. Marley

Given the importance of white dwarfs (WDs) in many fields of modern astrophysics, the precise knowledge of the actual degree of accuracy of the associated theoretical predictions is a primary task. In the first paper of a series dedicated…

Astrophysics · Physics 2009-11-13 P. G. Prada Moroni , O. Straniero

Cool white dwarfs with Teff < 6000 K are the remnants of the oldest stars that existed in our Galaxy. Their atmospheres, when properly characterized, can provide valuable information on white dwarf evolution and ultimately star formation…

Solar and Stellar Astrophysics · Physics 2012-10-12 Piotr M. Kowalski , Didier Saumon , Jay Holberg , Sandy Leggett

We present follow-up spectroscopy of 711 white dwarfs within 100 pc, and present a detailed model atmosphere analysis of the 100 pc white dwarf sample in the SDSS footprint. Our spectroscopic follow-up is complete for 83% of the white…

Solar and Stellar Astrophysics · Physics 2020-08-05 Mukremin Kilic , P. Bergeron , Alekzander Kosakowski , Warren R. Brown , Marcel A. Agueros , Simon Blouin

We investigate in detail the white dwarf cooling sequence of the globular cluster Messier 4. In particular we study the influence of various systematic uncertainties, both observational and theoretical, on the determination of the cluster…

PG 1159-035, a pre-white dwarf with T=140000 K, is the prototype of the PG1159 spectroscopic class and the DOV pulsating class. Changes in the star cause variations in its oscillation periods. The measurement of temporal change in the…

Astrophysics · Physics 2009-11-13 J. E. S. Costa , S. O. Kepler

In this study we compute the structure and evolution of carbon-oxygen DA white dwarfs by means of a detailed and updated evolutionary code. We treat the energy transport by convection within the formalism of the full spectrum turbulence…

Astrophysics · Physics 2016-08-30 L. G. Althaus , O. G. Benvenuto

The structure and dark matter halo core properties of dwarf spheroidal galaxies (dSphs) are investigated. A double-isothermal model of an isothermal stellar system, embedded in an isothermal dark halo core provides an excellent fit to the…

Astrophysics of Galaxies · Physics 2015-06-23 Andreas Burkert

We carry out a comprehensive smooth particle hydrodynamics simulation survey of double-degenerate white dwarf binary mergers of varying mass combinations in order to establish correspondence between initial conditions and remnant…

High Energy Astrophysical Phenomena · Physics 2015-06-03 Cody Raskin , Evan Scannapieco , Chris Fryer , Gabriel Rockefeller , F. X. Timmes

A calibration of the mixing-length parameter in the local mixing-length theory (MLT) is presented for the lower part of the convection zone in pure-hydrogen atmosphere white dwarfs. The parameterization is performed from a comparison of 3D…

Solar and Stellar Astrophysics · Physics 2015-06-23 P. -E. Tremblay , H. -G. Ludwig , B. Freytag , G. Fontaine , M. Steffen , P. Brassard