Multiple channels for the onset of magnetism in isolated white dwarfs

Understand

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 complex situation than a single mechanism valid for all stars.
• We show that in high-mass white dwarfs, which are probably the results of mergers, magnetic fields are extremely common and very strong, and appear immediately in the cooling phase.
• These fields may have been generated by a dynamo active during the merging.