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Related papers: Magnetic White Dwarfs with Heavy Elements

200 papers

The photospheres of the coolest helium-atmosphere white dwarfs are characterized by fluid-like densities. Under those conditions, standard approximations used in model atmosphere codes are no longer appropriate. Unfortunately, the majority…

Solar and Stellar Astrophysics · Physics 2018-08-29 Simon Blouin , Patrick Dufour , Nicole F. Allard

We improve on the model of the Galactic Magnetic Field (GMF) from Jansson \& Farrar (2012), which was constrained using all-sky rotation measures of extragalactic sources and polarized and unpolarized synchrotron emission data from WMAP. We…

Astrophysics of Galaxies · Physics 2017-07-14 Michael Unger , Glennys R. Farrar

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…

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

3D model atmospheres for giants, dwarfs, and white dwarfs, computed with the CO5BOLD code and part of the CIFIST grid, have been used for spectroscopic and asteroseismic studies. Unlike existing plane-parallel 1D structures, these…

Solar and Stellar Astrophysics · Physics 2015-06-16 P. -E. Tremblay , H. -G. Ludwig , B. Freytag , M. Steffen , E. Caffau

Measuring the mass-radius relation of individual white dwarfs is an empirically challenging task that has been performed for only a few dozen stars. We measure the white dwarf mass-radius relation using gravitational redshifts and radii of…

About half of white dwarfs (WDs) evolve to the DC state as they cool; the others become DQ or (temporarily?) DZ WDs. The recent magnetic survey of the local 20 pc volume has established a high frequency of magnetic fields among WDs older…

Solar and Stellar Astrophysics · Physics 2023-02-08 Andrei V. Berdyugin , Vilppu Piirola , Stefano Bagnulo , John D. Landstreet , Svetlana V. Berdyugina

Observational estimates of the lifetimes and inferred accretion rates from debris discs around polluted white dwarfs are often inconsistent with the predictions of models of shielded Poynting-Robertson drag on the dust particles in the…

Solar and Stellar Astrophysics · Physics 2021-01-05 Miriam A Hogg , Ry Cutter , Graham Wynn

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…

Solar and Stellar Astrophysics · Physics 2021-10-13 Chunhua Zhu , Helei Liu , Zhaojun Wang , Guoliang Lv

The T\"ubingen NLTE Model-Atmosphere Package (TMAP) calculates fully metal-line blanketed white dwarf model atmospheres and spectral energy distributions (SEDs) at a high level of sophistication. Such SEDs are easily accessible via the…

Solar and Stellar Astrophysics · Physics 2011-09-01 Thomas Rauch

Current estimates for white dwarfs with fields in excess of 1MG are about 10%; according to our first high-precision circular-polarimetric study of 12 bright white dwarfs with the VLT (Aznar Cuadrado et al. 2004) this number increases up to…

Astrophysics · Physics 2007-05-23 S. Jordan , R. Aznar Cuadrado , R. Napiwotzki , H. M. Schmid , S. K. Solanki

Many magnetic white dwarfs exhibit a polarised spectrum that periodically varies as the star rotates because the magnetic field is not symmetric about the rotation axis. In this work, we report the discovery that while weakly magnetic white…

Solar and Stellar Astrophysics · Physics 2024-11-18 S. Bagnulo , J. D. Landstreet

We investigate crystallization-driven convection in carbon-oxygen white dwarfs. We present a version of the mixing length theory (MLT) that self-consistently includes the effects of thermal diffusion and composition gradients, and provides…

Solar and Stellar Astrophysics · Physics 2024-07-01 Matias Castro-Tapia , Andrew Cumming , J. R. Fuentes

The knowledge of the structure of the magnetic field inside a blazar jet, as deduced from polarization observations at radio to optical wavelengths, is closely related to the formation and propagation of relativistic jets that result from…

High Energy Astrophysical Phenomena · Physics 2016-10-24 Manasvita Joshi , Alan P. Marscher , Markus Boettcher

Numerous observational evidence has suggested the presence of active meteorology in the atmospheres of brown dwarfs. A near-infrared brightness variability has been observed. Clouds have a major role in shaping the thermal structure and…

Earth and Planetary Astrophysics · Physics 2022-05-04 Maxence Lefèvre , Xianyu Tan , Elspeth K. H. Lee , R. T. Pierrehumbert

With the prevalence of wide-field, time-domain photometric sky surveys, the number of eclipsing white dwarf systems being discovered is increasing dramatically. An efficient method to follow these up will be key to determining any…

Due to the highly degeneracy of electrons in white dwarf stars, we expect that the relativistic effects play very important role in these stars. In the present article, we study the properties of the condensed matter in white dwarfs using…

Solar and Stellar Astrophysics · Physics 2020-03-24 M. I. Nouh , A. S. Saad , M. M. Elkhateeb , B. Korany

We used the mark weighted correlation functions (MCFs), $W(s)$, to study the large scale structure of the Universe. We studied five types of MCFs with the weighting scheme $\rho^\alpha$, where $\rho$ is the local density, and $\alpha$ is…

Cosmology and Nongalactic Astrophysics · Physics 2020-09-02 Yizhao Yang , Haitao Miao , Qinglin Ma , Miaoxin Liu , Cristiano G. Sabiu , Jaime Forero-Romero , Yuanzhu Huang , Limin Lai , Qiyue Qian , Yi Zheng , Xiao-Dong Li

We investigate the evolution of isolated, zero and finite temperature, massive, uniformly rotating and highly magnetized white dwarf stars under angular momentum loss driven by magnetic dipole braking. We consider the structure and thermal…

Solar and Stellar Astrophysics · Physics 2019-05-29 Laura Becerra , Kuantay Boshkayev , Jorge. A. Rueda , Remo Ruffini

We investigate the evolution of cooling helium atmosphere white dwarfs using a full evolutionary code, specifically developed for following the effects of element diffusion and gravitational settling on white dwarf cooling. The major…

Astrophysics · Physics 2016-08-16 James MacDonald , Margarita Hernanz , Jordi José

We present a prescription for parametrizing the chemical profile in the core of white dwarfs in the light of the recent discovery that pulsation modes may sometimes be deeply confined in some cool pulsating white dwarfs. Such modes may be…

Solar and Stellar Astrophysics · Physics 2017-01-18 N. Giammichele , S. Charpinet , G. Fontaine , P. Brassard