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Title: A Common Origin of Magnetism from Planets to White Dwarfs

Abstract

Isolated magnetic white dwarfs have field strengths ranging from kilogauss to gigagauss. However, the origin of the magnetic field has not been hitherto elucidated. Whether these fields are fossil, hence the remnants of original weak magnetic fields amplified during the course of the evolution of their progenitor stars, or are the result of binary interactions, or, finally, they are produced by other internal physical mechanisms during the cooling of the white dwarf itself, remains a mystery. At sufficiently low temperatures, white dwarfs crystallize. Upon solidification, phase separation of its main constituents, {sup 12}C and {sup 16}O, and of the impurities left by previous evolution occurs. This process leads to the formation of a Rayleigh–Taylor unstable liquid mantle on top of a solid core. This convective region, as it occurs in solar system planets like the Earth and Jupiter, can produce a dynamo able to yield magnetic fields of strengths of up to 0.1 MG, thus providing a mechanism that could explain magnetism in single white dwarfs.

Authors:
;  [1];  [2];  [3]
  1. Institut de Ciències de l’Espai (CSIC), Campus UAB, 08193 Cerdanyola (Spain)
  2. Institut d’Estudis Espacials de Catalunya, Ed. Nexus-201, c/Gran Capità 2-4, E-08034 Barcelona (Spain)
  3. School of Physics, University of Exeter, Stocker Road, Exeter EX4 4QL (United Kingdom)
Publication Date:
OSTI Identifier:
22654533
Resource Type:
Journal Article
Resource Relation:
Journal Name: Astrophysical Journal Letters; Journal Volume: 836; Journal Issue: 2; Other Information: Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
79 ASTROPHYSICS, COSMOLOGY AND ASTRONOMY; CARBON 12; EVOLUTION; IMPURITIES; INTERACTIONS; JUPITER PLANET; MAGNETIC FIELDS; MAGNETISM; OXYGEN 16; SOLAR SYSTEM; SOLIDIFICATION; SOLIDS; WHITE DWARF STARS

Citation Formats

Isern, Jordi, Külebi, Baybars, García-Berro, Enrique, and Lorén-Aguilar, Pablo. A Common Origin of Magnetism from Planets to White Dwarfs. United States: N. p., 2017. Web. doi:10.3847/2041-8213/AA5EAE.
Isern, Jordi, Külebi, Baybars, García-Berro, Enrique, & Lorén-Aguilar, Pablo. A Common Origin of Magnetism from Planets to White Dwarfs. United States. doi:10.3847/2041-8213/AA5EAE.
Isern, Jordi, Külebi, Baybars, García-Berro, Enrique, and Lorén-Aguilar, Pablo. Mon . "A Common Origin of Magnetism from Planets to White Dwarfs". United States. doi:10.3847/2041-8213/AA5EAE.
@article{osti_22654533,
title = {A Common Origin of Magnetism from Planets to White Dwarfs},
author = {Isern, Jordi and Külebi, Baybars and García-Berro, Enrique and Lorén-Aguilar, Pablo},
abstractNote = {Isolated magnetic white dwarfs have field strengths ranging from kilogauss to gigagauss. However, the origin of the magnetic field has not been hitherto elucidated. Whether these fields are fossil, hence the remnants of original weak magnetic fields amplified during the course of the evolution of their progenitor stars, or are the result of binary interactions, or, finally, they are produced by other internal physical mechanisms during the cooling of the white dwarf itself, remains a mystery. At sufficiently low temperatures, white dwarfs crystallize. Upon solidification, phase separation of its main constituents, {sup 12}C and {sup 16}O, and of the impurities left by previous evolution occurs. This process leads to the formation of a Rayleigh–Taylor unstable liquid mantle on top of a solid core. This convective region, as it occurs in solar system planets like the Earth and Jupiter, can produce a dynamo able to yield magnetic fields of strengths of up to 0.1 MG, thus providing a mechanism that could explain magnetism in single white dwarfs.},
doi = {10.3847/2041-8213/AA5EAE},
journal = {Astrophysical Journal Letters},
number = 2,
volume = 836,
place = {United States},
year = {Mon Feb 20 00:00:00 EST 2017},
month = {Mon Feb 20 00:00:00 EST 2017}
}
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