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| Paper: |
Rotation and Strong Magnetism of White Dwarfs |
| Volume: |
493, 19th European Workshop on White Dwarfs |
| Page: |
71 |
| Authors: |
Kissin, Y.; Thompson, C. |
| Abstract: |
We study the co-evolution of rotation and magnetism during the post-main sequence expansion of 1 and 5 M☉ stars. The magnetic field
is sourced by a dynamo operating near the core-envelope boundary, which is driven by the downward pumping of angular momentum though the envelope.
In stars with strong and magnetized main-sequence winds, this angular momentum must be supplied by a binary planetary or stellar companion.
Magnetic helicity is advected into the growing core as the magnetic field enforces solid-body rotation there, corresponding to a dipolar
magnetic field ∼ 106–107 G in the white dwarf (WD) remnant. We estimate the residual spin that results from a shutoff of the dynamo,
combined with decoupling of core and envelope, during the last stages of the AGB. Only a thin magnetized layer is left behind in a massive WD:
the ohmic transport time is typically less than a Gyr, suggesting that the incidence of strong magnetism in massive WDs
will be observed to decrease with age.
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