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The hydromagnetic structure of a neutron star accreting symmetrically at both magnetic poles is calculated as a function of accreted mass, M_a, and polar cap radius,starting from a centered magnetic dipole and evolving through a quasistatic…

Astrophysics · Physics 2009-11-10 D. J. B. Payne , A. Melatos

We investigate the evolution of the magnetic field of isolated pulsars and of neutron stars in different kinds of binary systems, assuming the field to be originally confined to the crust. Our results for the field evolution in isolated…

Astrophysics · Physics 2009-10-30 Sushan Konar , Dipankar Bhattacharya

A possible mechanism for screening of the surface magnetic field of an accreting neutron star, by the accreted material, is investigated. In particular, we investigate the nature of the evolution of the internal field configuration in the…

Astrophysics · Physics 2007-05-23 Sushan Konar , Arnab Rai Choudhuri

It has long been accepted that a possible mechanism for explaining the existence of magnetic white dwarfs is the merger of a binary white dwarf system, as there are viable mechanisms for producing sustainable magnetic fields within the…

Solar and Stellar Astrophysics · Physics 2015-06-15 Baybars Külebi , K. Yavuz Ekşi , Pablo Lorén-Aguilar , Jordi Isern , Enrique García-Berro

The magnetic fields of the accreting white dwarfs (WDs) in magnetic cataclysmic variables (mCVs) determine the accretion geometries, the emission properties, and the secular evolution of these objects. We determine the structure of the…

Astrophysics · Physics 2015-06-24 K. Beuermann , F. Euchner , K. Reinsch , S. Jordan , B. T. Gaensicke

The presence of a strong magnetic field is a feature common to a significant fraction of degenerate stars, yet little is understood about field origin and evolution. New observational constraints from volume-limited surveys point to a more…

Solar and Stellar Astrophysics · Physics 2022-08-24 Stefano Bagnulo , John D. Landstreet

Polluted white dwarfs are generally accreting terrestrial-like material that may originate from a debris belt like the asteroid belt in the solar system. The fraction of white dwarfs that are polluted drops off significantly for white…

Earth and Planetary Astrophysics · Physics 2020-02-19 Rebecca G. Martin , Mario Livio , Jeremy L. Smallwood , Cheng Chen

Studying the physical processes occurring in the region just above the magnetic poles of strongly magnetized, accreting binary neutron stars is essential to our understanding of stellar and binary system evolution. Perhaps more importantly,…

The influence of strong, large-scale magnetic fields on the structure and temperature distribution in white dwarf atmospheres is investigated. Magnetic fields may provide an additional component of pressure support, thus possibly inflating…

Astrophysics · Physics 2016-08-30 Ch. Fendt , D. Dravins

A number of cool white dwarfs with metal traces, of spectral types DAZ, DBZ, and DZ have been found to exhibit infrared excess radiation due to circumstellar dust. The origin of this dust is possibly a tidally disrupted asteroid that formed…

Solar and Stellar Astrophysics · Physics 2015-05-13 D. Koester

We consider the accretion process in a disk with magnetic fields that are dragged in from the interstellar medium by gravitational collapse. Two diffusive processes are at work in the system: (1) "viscous" torques exerted by turbulent and…

We investigate the luminosity and cooling of highly magnetized white dwarfs where cooling occurs by the diffusion of photons. We solve the magnetostatic equilibrium and photon diffusion equations to obtain the temperature and density…

Solar and Stellar Astrophysics · Physics 2018-10-19 Mukul Bhattacharya , Banibrata Mukhopadhyay , Subroto Mukerjee

A growing sample of white dwarfs (WDs) with metal-enriched atmospheres are accompanied by excess infrared emission, indicating that they are encircled by a compact dusty disk of solid debris. Such `WD debris disks' are thought to originate…

Earth and Planetary Astrophysics · Physics 2015-06-04 Brian D. Metzger , Roman R. Rafikov , Konstantin V. Bochkarev

Disk accretion onto a magnetized star occurs in a variety of astrophysical contexts, from young stars to X-ray pulsars. The magnetohydrodynamic interaction between the stellar field and the accreting matter can have a strong effect on the…

Astrophysics · Physics 2009-10-31 Dmitri A. Uzdensky , Arieh Konigl , Christof Litwin

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

Currently used model of spherical accretion onto a magnetized rotating neutron star encounters major difficulties in explaining the entry rate of accreting material into the stellar field and spin evolution of long-period X-ray pulsars.…

High Energy Astrophysical Phenomena · Physics 2012-05-08 N. R. Ikhsanov , L. A. Pustil'nik , N. G. Beskrovnaya

Due to the short settling times of metals in DA white dwarf atmospheres, any white dwarfs with photospheric metals must be actively accreting. It is therefore natural to expect that the metals may not be deposited uniformly on the surface…

Astrophysics · Physics 2009-11-13 M. H. Montgomery , S. E. Thompson , T. von Hippel

The theory of polar magnetic burial in accreting neutron stars predicts that a mountain of accreted material accumulates at the magnetic poles of the star, and that, as the mountain spreads equatorward, it is confined by, and compresses,…

Astrophysics · Physics 2008-11-26 D. J. B. Payne , A. Melatos

The amplitude of the gravitational radiation from an accreting neutron star undergoing polar magnetic burial is calculated. During accretion, the magnetic field of a neutron star is compressed into a narrow belt at the magnetic equator by…

Astrophysics · Physics 2008-11-26 A. Melatos , D. J. B. Payne

An extended magnetosphere of a strongly magnetized accreting white dwarf (known as a polar) prevents the formation of an accretion disk and the matter is channelled to the magnetic pole(s). A few such sources show quasi-periodic…

High Energy Astrophysical Phenomena · Physics 2020-10-14 Prasanta Bera