---
DOAJ_listed: '1'
OA_place: publisher
OA_type: diamond
PlanS_conform: '1'
_id: '22663'
abstract:
- lang: eng
  text: The detection of strong, large-scale magnetic fields at the surfaces of the
    oldest white dwarfs might point toward a hidden internal magnetic field slowly
    rising to the surface. In addition, strong magnetic fields have recently been
    measured through asteroseismology in the radiative interiors of red giant stars,
    the progenitors of white dwarfs. To investigate the potential connection between
    these observations, we revisited the fossil field framework using asteroseismic
    detections to constrain the strength of such magnetic fields as red giants evolve
    into the white dwarf stage. We assumed that the magnetic field was either created
    during the core convection on the main sequence or that it fills the radiative
    interior as the star evolves on the red giant branch. From these initial conditions,
    we evolved the magnetic flux, allowing for magnetic diffusion along the evolution
    of a modeled 1.5 M⊙ star. We find that measured field strengths in red giants
    attributed to the hydrogen-burning shell are compatible with the field amplitudes
    and emergence timescales of magnetized white dwarfs. On the contrary, magnetic
    fields generated solely from a convective-core dynamo on the main sequence and
    detectable on the red giant branch would be buried too deep in the star and would
    not match the breakout timescales or the field strengths of magnetic white dwarfs.
    Therefore, for us to connect magnetic fields observed along the late evolution
    of stars via a fossil field we would need to find a broadly magnetized internal
    radiative zone on the red giant branch.
acknowledgement: "The authors thank the referee for their helpful and constructive
  report, which has significantly enhanced the quality of the manuscript.\r\nThe authors
  thank I. Caiazzo, L. Ferrario, and L. Buchele for very useful discussions. L. Barrault,
  L. Bugnet, and L. Einramhof gratefully acknowledge support from the European Research
  Council (ERC) under the Horizon Europe\r\nprogramme (Calcifer; Starting Grant agreement
  N◦101165631). L. Barrault\r\nacknowledges the support of the Austrian Academy of
  Sciences through the Doctoral Fellowship Programme (DOC) of the Austrian Academy
  of Sciences 27648.\r\nWhile partially funded by the European Union, views and opinions
  expressed\r\nare, however, those of the authors only and do not necessarily reflect
  those of the European Union or the European Research Council. Neither the European
  Union\r\nnor the granting authority can be held responsible for them."
article_number: L14
article_processing_charge: No
article_type: original
arxiv: 1
author:
- first_name: Lukas
  full_name: Einramhof, Lukas
  id: f1497a1a-72ef-11ef-b75a-fd877bbf6e8c
  last_name: Einramhof
- first_name: Lisa Annabelle
  full_name: Bugnet, Lisa Annabelle
  id: d9edb345-f866-11ec-9b37-d119b5234501
  last_name: Bugnet
  orcid: 0000-0003-0142-4000
- first_name: L. M.
  full_name: Calcaferro, L. M.
  last_name: Calcaferro
- first_name: Lucas
  full_name: Barrault, Lucas
  id: 4471a8fd-32c1-11ee-a9a4-fb670d398f64
  last_name: Barrault
- first_name: S. B.
  full_name: Das, S. B.
  last_name: Das
citation:
  ama: Einramhof L, Bugnet LA, Calcaferro LM, Barrault L, Das SB. Magneto-archeology
    of white dwarfs. <i>Astronomy &#38; Astrophysics</i>. 2026;708. doi:<a href="https://doi.org/10.1051/0004-6361/202659069">10.1051/0004-6361/202659069</a>
  apa: Einramhof, L., Bugnet, L. A., Calcaferro, L. M., Barrault, L., &#38; Das, S.
    B. (2026). Magneto-archeology of white dwarfs. <i>Astronomy &#38; Astrophysics</i>.
    EDP Sciences. <a href="https://doi.org/10.1051/0004-6361/202659069">https://doi.org/10.1051/0004-6361/202659069</a>
  chicago: Einramhof, Lukas, Lisa Annabelle Bugnet, L. M. Calcaferro, Lucas Barrault,
    and S. B. Das. “Magneto-Archeology of White Dwarfs.” <i>Astronomy &#38; Astrophysics</i>.
    EDP Sciences, 2026. <a href="https://doi.org/10.1051/0004-6361/202659069">https://doi.org/10.1051/0004-6361/202659069</a>.
  ieee: L. Einramhof, L. A. Bugnet, L. M. Calcaferro, L. Barrault, and S. B. Das,
    “Magneto-archeology of white dwarfs,” <i>Astronomy &#38; Astrophysics</i>, vol.
    708. EDP Sciences, 2026.
  ista: Einramhof L, Bugnet LA, Calcaferro LM, Barrault L, Das SB. 2026. Magneto-archeology
    of white dwarfs. Astronomy &#38; Astrophysics. 708, L14.
  mla: Einramhof, Lukas, et al. “Magneto-Archeology of White Dwarfs.” <i>Astronomy
    &#38; Astrophysics</i>, vol. 708, L14, EDP Sciences, 2026, doi:<a href="https://doi.org/10.1051/0004-6361/202659069">10.1051/0004-6361/202659069</a>.
  short: L. Einramhof, L.A. Bugnet, L.M. Calcaferro, L. Barrault, S.B. Das, Astronomy
    &#38; Astrophysics 708 (2026).
corr_author: '1'
das_tickbox: '1'
dataavailabilitystatement: We used MESA version 24.08.1. All inlists and relevant
  files are available on Zenodo at https://doi.org/10.5281/zenodo.19232789
date_created: 2026-08-10T07:53:32Z
date_published: 2026-04-01T00:00:00Z
date_updated: 2026-08-11T05:49:20Z
day: '01'
ddc:
- '520'
department:
- _id: LiBu
- _id: GradSch
doi: 10.1051/0004-6361/202659069
external_id:
  arxiv:
  - '2601.15203'
file:
- access_level: open_access
  checksum: 61edee776603d7b879b06b3ea8d2bc89
  content_type: application/pdf
  creator: dernst
  date_created: 2026-08-11T05:46:02Z
  date_updated: 2026-08-11T05:46:02Z
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  file_name: 2026_AstronomyAstrophysics_Einramhof.pdf
  file_size: 3739424
  relation: main_file
  success: 1
file_date_updated: 2026-08-11T05:46:02Z
has_accepted_license: '1'
intvolume: '       708'
language:
- iso: eng
month: '04'
oa: 1
oa_version: Published Version
project:
- _id: 914d8549-16d5-11f0-9cad-bbe6324c93a9
  grant_number: '101165631'
  name: 'Unveiling the mysteries of stellar dynamics: a pioneering journey in magnetoasteroseismology'
- _id: 5b62812b-ab3d-11f0-914f-8f3a9cdb4af7
  grant_number: '27648'
  name: Unveiling the structure and dynamics of the deep convective core - radiative
    zone boundary throughout stellar evolution
publication: Astronomy & Astrophysics
publication_identifier:
  eissn:
  - 1432-0746
  issn:
  - 0004-6361
publication_status: published
publisher: EDP Sciences
quality_controlled: '1'
researchdata_availability: yes
scopus_import: '1'
status: public
supplementarymaterial: yes
title: Magneto-archeology of white dwarfs
tmp:
  image: /images/cc_by.png
  legal_code_url: https://creativecommons.org/licenses/by/4.0/legalcode
  name: Creative Commons Attribution 4.0 International Public License (CC-BY 4.0)
  short: CC BY (4.0)
type: journal_article
user_id: 2DF688A6-F248-11E8-B48F-1D18A9856A87
volume: 708
year: '2026'
...