J/ApJ/935/L12ivo://CDS.VizieR/J/ApJ/935/L12doi:10.26093/cds/vizier.19359012CDSBagnulo S.Landstreet J.D.2025-10-13T20:09:25Z2024-06-27T08:30:47ZCDS support team

CDS, Observatoire de Strasbourg, 11 rue de l'Universite, F-67000 Strasbourg, France

cds-question@unistra.frwhite-dwarf-starsmagnetic-fieldsstellar-agesThe presence of a strong magnetic field is a feature common to a significant fraction of degenerate stars, yet little is understood about the field's origin and evolution. New observational constraints from volume-limited surveys point to a more complex situation than a single mechanism valid for all stars. We show that in high-mass white dwarfs, which are probably the results of mergers, magnetic fields are extremely common and very strong and appear immediately in the cooling phase. These fields may have been generated by a dynamo active during the merging. Lower-mass white dwarfs, which are often the product of single-star evolution, are rarely detectably magnetic at birth, but fields appear very slowly, and very weakly, in about a quarter of them. What we may see is an internal field produced in an earlier evolutionary stage that gradually relaxes to the surface from the interior. The frequency and strength of magnetic fields continue to increase to eventually rival those of highly massive stars, particularly after the stars cool past the start of core crystallization, an effect that could be responsible for a dynamo mechanism similar to the one that is active in Earth's interior.2022ApJ...935L..12Bhttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/ApJ/935/L12CatalogResearchIsServedByTAP VizieR generic serviceIsServedByConesearch servicerelated-toIII/210 : Spectroscopically Identified White Dwarfs (McCook+, 1999)III/235 : Spectroscopically Identified White Dwarfs (McCook+, 2008)J/MNRAS/390/545 : Magnetic field & velocity of early M dwarfs (Donati+, 2008)J/MNRAS/425/1394 : High proper-motion white dwarfs (Kawka+, 2012)J/MNRAS/429/2934 : SDSS magnetic white dwarf stars (Kepler+, 2013)J/MNRAS/467/4970 : Cool DZ white dwarfs. I. (Hollands+, 2017)J/A+A/618/A113 : Spectropolarimetric survey of white dwarfs (Bagnulo+, 2018)J/MNRAS/499/1890 : Gaia white dwarfs within 40pc. II. (McCleery+, 2020)J/A+A/638/A131 : Radial velocities of 643 DA white dwarfs (Napiwotzki+, 2020)J/MNRAS/508/3877 : Catalogue of white dwarfs in Gaia EDR3 (Gentile+, 2021)https://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/ApJ/935/L12https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/ApJ/935/L12http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/ApJ/935/L12https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/ApJ/935/L12https://vizier.iucaa.in/viz-bin/votable?-source=J/ApJ/935/L12http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/ApJ/935/L12GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapCone search capability for table J/ApJ/935/L12/table2 (Physical parameters of the WDs checked for magnetic field in the context of a volume-limited survey)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/ApJ/935/L12/table2?https://vizier.iucaa.in/viz-bin/conesearch/J/ApJ/935/L12/table2?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/ApJ/935/L12/table2?GETtext/xml+votable180.050000true0.5446842-43.16538640.0055555555555555566/49 319 333 448 469 743 1077 1434 1731 2068 2157 2366 2536 2808 2890 3213 3222 3252 3258 3313 3345 3682 3819 4067 4375 4570 4668 5082 5190 5261 5827 6118 6274 6328 6579 6619 6705 6934 7267 7478 7483 7519 7652 7740 8361 8480 8546 8894 9071 9112 9458 9651 9751 9779 9985 10005 10169 10173 11020 11031 11131 11193 11511 11529 11642 11645 11784 11984 12157 12268 12738 12791 13013 13103 13295 13391 13668 14187 14388 14391 14586 14594 15209 15280 15335 15462 15474 15620 15651 16078 16158 16344 16433 16697 16895 16955 17020 17094 17158 17181 17331 17463 17625 17666 17879 18139 18368 18383 18415 18556 18902 18953 19141 19655 20155 20404 20940 21194 21396 21479 22214 22300 22345 22638 22709 22757 22803 22870 23101 23174 23457 23468 23497 23591 24102 24713 24795 24912 25250 25255 25276 25460 25712 25792 26321 26386 26396 26678 26740 26916 27078 27395 28271 28559 28574 28901 29194 29486 29505 29777 29855 30093 30509 30659 30694 30696 31172 31179 31549 31735 31862 31956 32617 32715 32781 33015 33198 33243 33322 33384 33634 35079 35412 35490 35790 36416 36567 37024 37125 37174 37183 37248 37464 37473 37477 37523 37815 37890 38036 38188 38381 38890 38955 39336 39397 39421 39535 39709 39807 40070 40283 40623 40682 40747 40879 40944 40959 41017 41125 41638 41693 41705 42070 42091 42692 42700 42760 43239 43536-43537 44449 44639 45110 45173 45177 45386 45649 45782 46031 46598 46709 46841 47476 47907 47957 48254 48296 48358 48621 48724 48728 49125https://cdsarc.cds.unistra.fr/viz-bin/moc/J/ApJ/935/L12?format=asciidefaultJ/ApJ/935/L12/table2Physical parameters of the WDs checked for magnetic field in the context of a volume-limited surveyrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintf_Name[b] b=Magnetic WD flagmeta.codecharNameWD Name (1)meta.id;meta.maincharprimarySNameSimbad main identifier(s)meta.idcharSpTWD Spectral class (2)src.spTypecharGmag[8.5/17.2] G magnitude (3)magphot.mag;em.opt.VfloatATMChemical composition of atmosphere (4)meta.notecharTeff[3821/39304] Effective temperatureKphys.temperature.effectiveintWDM[0.39/1.28] WD Mass, solar units (5)solMassphys.massfloatAge[0.02/9.62] Age, Gyr (6)Gyrtime.agefloatDist[2.7/39.7] Distance, parsecs (7)pcpos.distancefloatB[0.0/670.0] Mean magnetic field modulus, MG (8)MGphys.magFieldfloatNewNew magnetic field measurements (link to Table 1)meta.ref.urlcharRefReferences (9)meta.refcharSimbadSimbad column added by the CDSmeta.ref.urlchar_RARight Ascension (J2000) from SIMBAD (not part of the original data)degpos.eq.ra;meta.main_DEDeclination (J2000) from SIMBAD (not part of the original data)degpos.eq.dec;meta.mainJ/ApJ/935/L12/table1New magnetic field measurements of young WDs between 20 and 40pcrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintNameWD name (1)meta.id;meta.maincharInstrInstrumentmeta.id;instrcharGrismGrism or Gratingmeta.notecharObs[2015/2022] Observation date, yearstime.epoch;obsExpTime[1368/7060] Exposure timestime.duration;obs.exposureintSN[34/720] Signal-noise, Angstrom-1stat.snrintBz[-6.39/10.0]? Mean Longitudinal Magnetic FieldkGphys.magFieldfloatnullablee_Bz[0.31/12.0]? Uncertainty in BzkGstat.errorfloatnullableNotesNotes on source (2)meta.notechar