A new weak-field magnetic DA white dwarf in the local 20 pc volume. The frequency of magnetic fields in DA stars

Abstract

We report the discovery of a new magnetic DA white dwarf (WD), WD0011-721, which is located within the very important 20pc volume-limited sample of the closest WDs to the Sun. This star has a mean field modulus <|B|> of 343 kG, and from the polarisation signal we deduce a line-of-sight field component of 75 kG. The magnetic field is sufficiently weak to have escaped detection in classification spectra. We then present a preliminary exploration of the data concerning the frequency of such fields among WDs with hydrogen-rich atmospheres (DA stars). We find that 20 +- 5% of the DA WDs in this volume have magnetic fields, mostly weaker than 1 MG. Unlike the slow field decay found among the magnetic Bp stars of the upper main sequence, the WDs in this sample show no evidence of magnetic field or flux changes over several Gyr.

References in corpus (12)

• Magnetic White Dwarfs
• Binary Star Origin of High Field Magnetic White Dwarfs
• Spectropolarimetric Survey of Hydrogen-rich White Dwarf Stars
• Searching for links between magnetic fields and stellar evolution III. Measurement of magnetic fields in open cluster Ap stars with ESPaDOnS
• The fraction of DA white dwarfs with kilo-Gauss magnetic fields
• The Solar Neighborhood. XXXIX. Parallax Results from the CTIOPI and NOFS Programs: 50 New Members of the 25 Parsec White Dwarf Sample
• The incidence of magnetic fields in cool DZ white dwarfs
• The Solar Neighborhood. XIX. Discovery and Characterization of 33 New Nearby White Dwarf Systems
• The pecular magnetic field morphology of the white dwarf WD 1953-011: evidence for a large-scale magnetic flux tube?
• Monitoring and modelling of white dwarfs with extremely weak magnetic fields
• The long term polarimetric variability of the strongly magnetic white dwarf Grw+70${}^{\circ }$8247
• Discovery of kilogauss magnetic fields on the nearby white dwarfs WD1105-340 and WD2150+591

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