Discovery of kilogauss magnetic fields on the nearby white dwarfs WD1105-340 and WD2150+591

Abstract

Magnetic fields are present in roughly 10% of white dwarfs. These fields affect the structure and evolution of such stars, and may provide clues about their earlier evolution history. Particularly important for statistical studies is the collection of high-precision spectropolarimetric observations of (1) complete magnitude-limited samples and (2) complete volume-limited samples of white dwarfs. In the course of one of our surveys we have discovered previously unknown kG-level magnetic fields on two nearby white dwarfs, WD1105-340 and WD2150+591. Both stars are brighter than m_V = 15. WD2150+591 is within the 20-pc volume around the Sun, while WD1105-340 is just beyond 25 pc in distance. These discoveries increase the small sample of such weak-field white dwarfs from 21 to 23 stars. Our data appear consistent with roughly dipolar field topology, but it also appears that the surface field structure may be more complex on the older star than on the younger one, a result similar to one found earlier in our study of the weak-field stars WD2034+372 and WD2359-434. This encourages further efforts to uncover a clear link between magnetic morphology and stellar evolution.

References in corpus (21)

• Gaia Data Release 2. Summary of the contents and survey properties
• The Gaia mission
• Magnetic fields of non-degenerate stars
• Magnetic White Dwarfs
• A Spectroscopic Survey & Analysis of Bright, Hydrogen-Rich White Dwarfs
• New white dwarf and subdwarf stars in the Sloan Digital Sky Survey Data Release 12
• Binary Star Origin of High Field Magnetic White Dwarfs
• Know Your Neighborhood: A Detailed Model Atmosphere Analysis of Nearby White Dwarfs
• High-resolution UVES/VLT spectra of white dwarfs observed for the ESO SN Ia Progenitor Survey. III. DA white dwarfs
• Magnetic White Dwarfs from the SDSS. The First Data Release
• The Gaia 20 pc white dwarf sample
• Discovery of kilogauss magnetic fields in three DA white dwarfs
• On The Evolution of Magnetic White Dwarfs
• The FORS1 catalogue of stellar magnetic field measurements
• The Solar Neighborhood. XXXIX. Parallax Results from the CTIOPI and NOFS Programs: 50 New Members of the 25 Parsec White Dwarf Sample
• The polluted atmospheres of cool white dwarfs and the magnetic field connection
• The Solar Neighborhood. XIX. Discovery and Characterization of 33 New Nearby White Dwarf Systems
• Evidence of enhanced magnetism in cool, polluted white dwarfs
• Searching for the weakest detectable magnetic fields in white dwarfs. Highly-sensitive measurements from first VLT and WHT surveys
• 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 Eri B
• Monitoring and modelling of white dwarfs with extremely weak magnetic fields

Cited by in corpus (12)

• Magnetic fields in isolated and interacting white dwarfs
• New insight into the magnetism of degenerate stars from the analysis of a volume limited sample of white dwarfs
• $\text{Gaia}$ white dwarfs within 40 pc I: spectroscopic observations of new candidates
• Multiple channels for the onset of magnetism in isolated white dwarfs
• Discovery of six new strongly magnetic white dwarfs in the 20 pc local population
• A new weak-field magnetic DA white dwarf in the local 20 pc volume. The frequency of magnetic fields in DA stars
• Single magnetic white dwarfs with Balmer emission lines: A small class with consistent physical characteristics as possible signposts for close-in planetary companions
• Highly sensitive search for magnetic fields in white dwarfs using broad-band circular polarimetry
• DAHe white dwarfs from the DESI survey
• Can we reveal the core-chemical composition of ultra-massive white dwarfs through their magnetic fields?
• A network of cooler white dwarfs as infrared standards for flux calibration
• A numerical code for the analysis of magnetic white dwarf spectra that includes field effects on the chemical equilibrium