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The absence of magnetic white dwarfs with a non-degenerate low-mass stellar companion in a wide binary is still very intriguing and at odds with the hypothesis that magnetic white dwarfs are the progenies of the magnetically peculiar Ap/Bp stars. On the other hand, we cannot resort to a process that impedes the generation of a strong magnetic field in the main or pre-main sequence progenitors of white dwarfs if they are in a multiple stellar system, because such a process would also prevent the formation of magnetic cataclysmic variables consisting of a magnetic white dwarf accreting mass from a low-mass companion. This is the reason why it has been proposed that fields in white dwarfs may be linked to their binarity and are generated through a dynamo mechanism during common envelope evolution.
We report the discovery of a new, polluted, magnetic white dwarf in the Luyten survey of high-proper motion stars. High-dispersion spectra of NLTT 7547 reveal a complex heavy element line spectrum in a cool (~5 200 K) hydrogen-dominated atmosphere sh
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 origin of
High-field magnetic white dwarfs have been long suspected to be the result of stellar mergers. However, the nature of the coalescing stars and the precise mechanism that produces the magnetic field are still unknown. Here we show that the hot, convec
A significant fraction of white dwarfs possess a magnetic field with strengths ranging from a few kG up to about 1000 MG. However, the incidence of magnetism varies when the white dwarf population is broken down into different spectral types providin
We investigate whether the recently suggested rotation and crystallization driven dynamo can explain the apparent increase of magnetism in old metal polluted white dwarfs. We find that the effective temperature distribution of polluted magnetic white