It is not yet understood how the magnetic fields of white dwarfs are
formed, or how they evolve during white dwarf cooling. In spite of
many detections of megagauss fields in white dwarfs, mostly very faint,
little is known about the low-field regime, and very little modelling
of the fields of individual white dwarfs is available. This current ISIS survey
is intended to increase the very small sample and to provide data for
detailed modelling, and ultimately to provide data to constrain field
formation scenarios.
It is found that ISIS is a very powerful tool for searches for such
weak fields; it is able to detect fields of tens of kilogauss using either
Hydrogen-alpha spectroscopy or spectropolarimetry of Hydrogen or Helium line wings, or
both, in white dwarfs fainter than V = 15.
More information:
J. D. Landstreet, S. Bagnulo, A. Martin, and G. Valyavin, 2016, "Discovery of an extremely weak magnetic field in the white dwarf LTT 16093 WD2047+372", A&A, 591, A80 [ADS ].