On the incidence of weak magnetic fields in DA white dwarfs

  title={On the incidence of weak magnetic fields in DA white dwarfs},
  author={John D Landstreet and S Bagnulo and G. Valyavin and Luca Fossati and Stefan Jordan and Dmitry Monin and Gregg A. Wade},
  journal={Astronomy and Astrophysics},
Context. About 10 % of white dwarfs have magnetic fields with strength i n the range between about 10 5 and 5 10 8 G. It is not known whether the remaining white dwarfs are not magnetic, or if they have magnetic fields too weak to be detected with the techni ques adopted in the large surveys. Information is particularly l acking for the cooler (and generally fainter) white dwarfs. Aims. We describe the results of the first survey specifically devis ed to clarify the detection frequency of kG… Expand

Figures and Tables from this paper

Monitoring and modelling of white dwarfs with extremely weak magnetic fields - WD 2047+372 and WD 2359-434
Magnetic fields are detected in a few percent of white dwarfs. The number of such magnetic white dwarfs known is now some hundreds. Fields range in strength from a few kG to several hundred MG.Expand
Magnetic White Dwarfs
In this paper we review the current status of research on the observational and theoretical characteristics of isolated and binary magnetic white dwarfs (MWDs).Magnetic fields of isolated MWDs areExpand
Discovery of an extremely weak magnetic field in the white dwarf LTT 16093 = WD 2047+372
Context. Magnetic fields have been detected in several hundred white dwarfs, with strengths ranging from a few kG to several hundred MG. Only a few of the known fields have a mean magnetic fieldExpand
A new weak-field magnetic DA white dwarf in the local 20 pc volume
We report the discovery of a new magnetic DA white dwarf (WD), WD 0011 − 721, which is located within the very important 20 pc volume-limited sample of the closest WDs to the Sun. This star has aExpand
A novel and sensitive method for measuring very weak magnetic fields of DA white dwarfs. A search for a magnetic field at the 250 G level in 40 Eridani B
Searches for magnetic fields in white dwarfs have clarified both the frequency of occurrence and the global structure of the fields found down to field strengths of the order of 500 kG. Below thisExpand
Can magnetic fields suppress convection in the atmosphere of cool white dwarfs? A case study on WD2105−820
Around 10 per cent of white dwarfs exhibit global magnetic structures with fields ranging from 1 kG to hundreds of MG. Recently, the first radiation magnetohydrodynamics simulations of the atmosphereExpand
A magnetic white dwarf with five H α components
G183−35 is an unusual white dwarf that shows an H α line split into five components, instead of the usual three components seen in strongly magnetic white dwarfs. Potential explanations for theExpand
Suppression of cooling by strong magnetic fields in white dwarf stars
It is found that strong fields are sufficient to suppress convection over the entire surface in cool magnetic white dwarf, which inhibits their cooling evolution relative to weakly magnetic and non-magnetic white dwarfs, making them appear younger than they truly are. Expand
New insight into the magnetism of degenerate stars from the analysis of a volume-limited sample of white dwarfs
Many stars evolve into magnetic white dwarfs (MWDs), and observations may help to understand when the magnetic field appears at the stellar surface, if and how it evolves during the cooling phase,Expand
Magnetic fields in isolated and interacting white dwarfs
Abstract The magnetic white dwarfs (MWDs) are found either isolated or in interacting binaries. The isolated MWDs divide into two groups: a high field group ( 10 5 – 10 9  G) comprising some 13 ± 4 %Expand


The Fraction of DA White Dwarfs with Kilo-Gauss Magnetic Fields
Context. Weak magnetic fields have been searched for on only a small number of white dwarfs. Current estimates find that about 10% of all white dwarfs have fields in excess of 1 MG; according toExpand
A search for kilogauss magnetic fields in white dwarfs and hot subdwarf stars
We present new results of a survey for weak magnetic fields among DA white dwarfs, including some brighter hot subdwarf stars. We have detected variable circular polarization in the Hα line of theExpand
Discovery of kilogauss magnetic fields in three DA white dwarfs
We have detected longitudinal magnetic fields between 2 and 4 kG in three (WD 0446−790, WD 1105−048, WD 2359−434) out of a sample of 12 normal DA white dwarfs by using optical spectropolarimetry doneExpand
A study of high proper-motion white dwarfs – I. Spectropolarimetry of a cool hydrogen-rich sample†
We conducted a spectropolarimetic survey of 58 high proper-motion white dwarfs which achieved uncertainties of >rsim 2 kG in the Hα line and >rsim 5 kG in the upper Balmer line series. The surveyExpand
Analysis of hydrogen-rich magnetic white dwarfs detected in the Sloan Digital Sky Survey
Context A large number of magnetic white dwarfs discovered in the SDSS have so far only been analyzed by visual comparison of the observations with relatively simple models of the radiationExpand
Magnetic fields and rotation of the white dwarfs 40 Eri B and WD 0009+501
We describe the results of our magnetometric monitoring of two white dwarfs: 40 Eri B and WD 0009+501. We found periodic variations in the longitudinal magnetic field of 40 Eri B. The fieldExpand
Spectropolarimetric Survey of Hydrogen‐rich White Dwarf Stars
We have conducted a survey of 61 southern white dwarfs searching for magnetic fields using Zeeman spectropolarimetry. Our objective is to obtain a magnetic field distribution for these objects and,Expand
Weak magnetic fields in Ap/Bp stars - Evidence for a dipole field lower limit and a tentative interp
Aims. We investigated a sample of 28 well-known spectroscopically-identified magnetic Ap/Bp stars, with weak, poorly-determined or previously undetected magnetic fields. The aim of this study is toExpand
The Peculiar Magnetic Field Morphology of the White Dwarf WD 1953–011: Evidence for a Large-Scale Magnetic Flux Tube?
We present and interpret new spectropolarimetric observations of the magnetic white dwarf WD 1953–011. Circular polarization and intensity spectra of the Hα spectral line demonstrate the presence ofExpand
Discoveries of magnetic fields in 26 white dwarfs since 1970 do not negate the basic inference from the work of Babcock - that most of the over 1000 known white dwarfs do not have strong magneticExpand