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We study the influence of initial conditions on the magnetic field amplification during the collapse of a magnetised gas cloud. We focus on the dependence of the growth and saturation level of the dynamo generated field on the turbulent…

Solar and Stellar Astrophysics · Physics 2015-06-04 Sharanya Sur , Christoph Federrath , Dominik R. G. Schleicher , Robi Banerjee , Ralf S. Klessen

Generally the virial theorem provides a relation between various components of energy integrated over a system. This helps us to understand the underlying equilibrium. Based on the virial theorem we can estimate, for example, the maximum…

Solar and Stellar Astrophysics · Physics 2020-10-21 Banibrata Mukhopadhyay , Arnab Sarkar , Christopher A. Tout

When a star gets tidally disrupted by a supermassive black hole, its magnetic field is expected to pervade its debris. In this paper, we study this process via smoothed particle magnetohydrodynamical simulations of the disruption and early…

High Energy Astrophysical Phenomena · Physics 2017-06-28 Clément Bonnerot , Daniel J. Price , Giuseppe Lodato , Elena M. Rossi

The origin of magnetic fields in isolated and binary white dwarfs has been investigated in a series of recent papers. One proposal is that magnetic fields are generated through an alpha-omega dynamo during common envelope evolution. Here we…

Solar and Stellar Astrophysics · Physics 2018-10-16 Gordon Briggs , Lilia Ferrario , Christopher Tout , Dayal Wickramasinghe

The origin of magnetic fields in white dwarfs (WDs) remains mysterious. Magnetic WDs are traditionally associated with field strengths $\gtrsim1\,\mathrm{MG}$, set by the sensitivity of typical spectroscopic magnetic field measurements.…

Solar and Stellar Astrophysics · Physics 2025-01-30 Nicholas Z. Rui , Jim Fuller , J. J. Hermes

Stars more massive than $\sim 1.3$ M$_\odot$ are known to develop a convective core during the main-sequence: the dynamo process triggered by this convection could be the origin of a strong magnetic field inside the core of the star,…

Solar and Stellar Astrophysics · Physics 2021-01-20 L. Bugnet , V. Prat , S. Mathis , R. A. García , S. Mathur , K. Augustson , C. Neiner , M. J. Thompson

Since their initial discovery, the origin of isolated white dwarfs (WDs) with magnetic fields in excess of $\sim$1 MG has remained a mystery. Recently, the formation of these high-field magnetic WDs has been observationally linked to strong…

Solar and Stellar Astrophysics · Physics 2015-05-30 J. Nordhaus

The evolution of the magnetic field of an accreting magnetic white dwarf with an initially dipolar field at the surface has been studied for non-spherical accretion under simplifying assumptions. Accretion on to the polar regions tends to…

High Energy Astrophysical Phenomena · Physics 2015-05-13 C. M. Zhang , D. T. Wickramasinghe , L. Ferrario

The origin and the magnitude of the inter-galactic magnetic field is of primordial importance in the global picture of magnetic field evolution, as it is considered to be the missing link between galactic magnetic fields and cluster…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-14 Yohan Dubois , Romain Teyssier

In early-type stars a fossil magnetic field may be generated during the star formation process or be the result of a stellar merger event. Surface magnetic fields are thought to be erased by (sub)surface convection layers, which typically…

Solar and Stellar Astrophysics · Physics 2020-06-17 Adam S. Jermyn , Matteo Cantiello

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

Recent high-resolution 53-$\mu$m polarimetric observations from SOFIA/HAWC+ have revealed the inferred plane-of-the-sky magnetic field (B-field) orientation in the Galactic center's Circum-Nuclear Disk (CND). The B-field is mostly aligned…

Astrophysics of Galaxies · Physics 2023-07-05 J. A. Guerra , E. Lopez-Rodriguez , D. T. Chuss , N. O. Butterfield , J. T. Schmelz

Sufficiently old white dwarfs cool down through a convective envelope that directly couples their degenerate cores to the surface. Magnetic fields may inhibit this convection by stiffening the criterion for convective instability. We…

Solar and Stellar Astrophysics · Physics 2024-09-13 Sivan Ginzburg

Aims. We investigate the cosmological evolution of large- and small-scale magnetic fields in galaxies in the light of present models of formation and evolution of galaxies. Methods. We use the dynamo theory to derive the timescales of…

Astrophysics · Physics 2009-11-13 Tigran G. Arshakian , Rainer Beck , Marita Krause , Dmitry Sokoloff

The magnetic white dwarfs (MWDs) are found either isolated or in interacting binaries. They divide into two groups: a high field group (0.1-1,000MegaGauss) comprising some 13% of all white dwarfs (WDs), and a low field group (B<0.1MG) whose…

Solar and Stellar Astrophysics · Physics 2020-01-29 Lilia Ferrario , D. T. Wickramasinghe , Adela Kawka

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

A significant fraction of white dwarfs harbour a magnetic field with strengths ranging from a few kG up to about 1000 MG. The fraction appears to depend on the specific class of white dwarfs being investigated and may hold some clues to the…

Solar and Stellar Astrophysics · Physics 2018-01-18 A. Kawka

Context. Red-giant stars may engulf planets. This may increase the rotation rate of their convective envelope, which could lead to strong dynamo-triggered magnetic fields. Aims. We explore the possibility of generating magnetic fields in…

With the increasing number of observed magnetic white dwarfs (WDs), the role of magnetic field of the WD in both single and binary evolutions should draw more attentions. In this study, we investigate the WD/main-sequence star binary…

High Energy Astrophysical Phenomena · Physics 2019-06-07 Iminhaji Ablimit , Keiichi Maeda

To shed light on the origin of magnetic symbiotic stars, we investigated the system FN Sgr in detail. We searched for a reasonable formation pathway to explain its stellar and binary parameters including the magnetic field of the accreting…

Solar and Stellar Astrophysics · Physics 2024-06-19 Diogo Belloni , Joanna Mikołajewska , Matthias R. Schreiber