Clues to the origin and properties of magnetic white dwarfs

Abstract

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 providing clues on the formation of magnetic fields in white dwarfs. Several scenarios for the origin of magnetic fields have been proposed from a fossil field origin to dynamo generation at various stages of evolution. Offset dipoles are often assumed sufficient to model the field structure, however time-resolved spectropolarimetric observations have revealed more complex structures such as magnetic spots or multipoles. Surface mapping of these field structures combined with measured rotation rates help distinguish scenarios involving single star evolution from other scenarios involving binary interactions. I describe key observational properties of magnetic white dwarfs such as age, mass, and field strength, and confront proposed formation scenarios with these properties.

Review article for the IAU Symposium 357: White dwarfs as probes of fundamental physics and tracers of planetary, stellar & galactic evolution

References in corpus (14)

• Binary Star Origin of High Field Magnetic White Dwarfs
• White Dwarf Rotation as a Function of Mass and a Dichotomy of Mode Linewidths: Kepler Observations of 27 Pulsating DA White Dwarfs Through K2 Campaign 8
• Spectropolarimetric Survey of Hydrogen-rich White Dwarf Stars
• Rare White dwarf stars with carbon atmospheres
• Hot DQ White Dwarfs: Something Different
• Measurements of Physical Parameters of White Dwarfs: A Test of the Mass-Radius Relation
• A common origin of magnetism from planets to white dwarfs
• An unusual white dwarf star may be a surviving remnant of a subluminous Type Ia supernova
• A New Generation of Cool White Dwarf Atmosphere Models. IV. Revisiting the Spectral Evolution of Cool White Dwarfs
• Merging Binary Stars and the magnetic white dwarfs
• The incidence of magnetic fields in cool DZ white dwarfs
• The pecular magnetic field morphology of the white dwarf WD 1953-011: evidence for a large-scale magnetic flux tube?
• Enigmas from the Sloan Digital Sky Survey DR7 Kleinman White Dwarf Catalog
• An ancient double degenerate merger in the Milky Way halo

Cited by in corpus (5)

• Catalog of magnetic white dwarfs with hydrogen dominated atmospheres
• A Short Intense Dynamo at the Onset of Crystallization in White Dwarfs
• Effects of Magnetic Fields in Hot White Dwarfs
• The Formation of Discs in the Interior of AGB Stars from the Tidal Disruption of Planets and Brown Dwarfs
• Revealing the nature of long-period transients with space-based gravitational-wave interferometers