Evidence of enhanced magnetism in cool, polluted white dwarfs

2018/11/08 by A. Kawka, Adela Kawka, Stephane Vennes +4 · 1 citation
Earth and Planetary Sciences · Physics and Astronomy · #Astro and Planetary Science #Astrobiology #Astronomy #Astrophysics #Condensed matter physics #High-pressure geophysics and materials #Magnetism #Physics #Stars #Stellar, planetary, and galactic studies #White dwarf #astro-ph.SR

paper · pdf · doi:10.1093/mnras/sty3048

Accepted for publication in MNRAS

arxiv created 2018/11/08 · openalex publication_date 2018/11/15 · arxiv updated 2018/11/28 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/05

Abstract

We report the discovery of a new, polluted, magnetic white dwarf in the Luyten survey of high-proper motion stars. High-dispersion spectra of NLTT 7547 reveal a complex heavy element line spectrum in a cool (≈5200 K) hydrogen-dominated atmosphere showing the effect of a surface averaged field of 163 kG, consistent with a 240 kG centred dipole, although the actual field structure remains uncertain. The abundance pattern shows the effect of accreted material with a distinct magnesium-rich flavour. Combined with earlier identifications, this discovery supports a correlation between the incidence of magnetism in cool white dwarfs and their contamination by heavy elements.

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• Discovery of kilogauss magnetic fields on the nearby white dwarfs WD 1105–340 and WD 2150+591