Are white dwarf magnetic fields in close binaries generated during common-envelope evolution?
arXiv:1910.08582 · doi:10.1093/mnras/stz3601
Abstract
Understanding the origin of the magnetic fields in white dwarfs (WDs) has been a puzzle for decades. A scenario that has gained considerable attention in the past years assumes that such magnetic fields are generated through a dynamo process during common-envelope evolution. We performed binary population models using an up-to-date version of the BSE code to confront the predictions of this model with observational results. We found that this hypothesis can only explain the observed distribution of WD magnetic fields in polars and pre-polars and the low-temperature WDs in pre-polars if it is re-scaled to fit the observational data. Furthermore, in its present version, the model fails to explain the absence of young close detached WD+M-dwarf binaries harbouring hot magnetic WDs and predicts that the overwhelming majority of WDs in close binaries should be strongly magnetic, which is also in serious conflict with the observations. We conclude that either the common-envelope dynamo scenario needs to be substantially revised or a different mechanism is responsible for the generation of strong WD magnetic fields in close binaries.
7 pages; accepted for publication in MNRAS
References in corpus (14)
- Magnetic White Dwarfs
- Post-common-envelope binaries from SDSS. IX: Constraining the common-envelope efficiency
- Binary Star Origin of High Field Magnetic White Dwarfs
- Spectropolarimetric Survey of Hydrogen-rich White Dwarf Stars
- Evolution of a buried magnetic field in the central compact object neutron stars
- Monte Carlo simulations of post-common-envelope white dwarf + main sequence binaries: comparison with the SDSS DR7 observed sample
- A common origin of magnetism from planets to white dwarfs
- The evolutionary status of Cataclysmic Variables: Eclipse modelling of 15 systems
- Evidence for reduced magnetic braking in polars from binary population models
- Magnetic Field Amplification During the Common Envelope Phase
- The population of white dwarf-main sequence binaries in the SDSS DR 12
- The origin of single low-mass WDs: another problem that consequential angular momentum loss in CVs might solve
- Enigmas from the Sloan Digital Sky Survey DR7 Kleinman White Dwarf Catalog
- Hypercritical accretion onto a magnetized neutron star surface: a numerical approach