---
DOAJ_listed: '1'
OA_place: publisher
OA_type: diamond
PlanS_conform: '1'
_id: '20931'
abstract:
- lang: eng
text: "Context. Asymmetries in the observed rotational splittings of a multiplet
contain information about the star’s rotation profile and internal magnetic field.
Moreover, the frequency regularities of multiplets can be used for mode identification.
However, to exploit this information, highly accurate theoretical predictions
are needed.\r\n\r\nAims. We aim to quantify the difference in the predicted mode
asymmetries between a 1D perturbative method and a 2D method that includes a 2D
stellar structure model, which takes rotation into account. We then place these
differences between 1D and 2D methods in the context of asteroseismic measurements
of internal magnetic fields. We only focus on the asymmetries and not on possible
additional frequency peaks that can arise when the magnetic and rotation axis
are misaligned.\r\n\r\nMethods. We coupled the 1D pulsation codes GYRE and StORM
to the 2D stellar structure code ESTER and compared the oscillation predictions
with the results from the 2D TOP pulsation code. We focused on zero-age main-sequence
models representative of rotating β Cephei pulsators spinning at up to 20 per
cent of the critical Keplerian rotation rate. Specifically, we investigated low-radial-order
gravity and pressure modes.\r\n\r\nResults. We find a generally good agreement
between the oscillation frequencies resulting from the 1D and 2D pulsation codes.
We report differences in predicted mode multiplet asymmetries of mostly below
0.06 d−1. Since the magnetic asymmetries are small compared to the differences
in the rotational asymmetries resulting from the 1D and 2D predictions, accurate
measurements of the magnetic field are in most cases challenging.\r\n\r\nConclusions.
Differences in the predicted mode asymmetries of a rotating star between 1D perturbative
methods and 2D non-perturbative methods can greatly hinder accurate measurements
of internal magnetic fields in main-sequence pulsators with low-order modes. Nevertheless,
reasonably accurate measurements could be possible with npg ≥ 2 modes if the internal
rotation is roughly below 10 per cent of the Keplerian critical rotation frequency
for (aligned) magnetic fields of the order of a few hundred kilogauss. While the
differences between the 1D and 2D frequency predictions are mostly too large for
internal magnetic field detections, the rotational asymmetries predicted by StORM
are in general accurate enough for asteroseismic modelling of the stellar rotation
in main-sequence stars with identified low-order modes."
acknowledgement: 'We thank the anonymous referee for their comments on the manuscript,
Dario Fritzewski for providing the distribution of fractions of critical rotation
for the β Cephei sample, and Zhao Guo for the discussions. The research leading
to these results has received funding from the European Research Council (ERC) under
the Horizon Europe programme (Synergy Grant agreement N°101071505: 4D-STAR). While
partially funded by the European Union, views and opinions expressed are 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 nor the granting authority
can be held responsible for them. V.V. acknowledges support from the Research Foundation
Flanders (FWO) under grant agreement N°1156923N (PhD Fellowship). S.B.D. acknowledges
funding from the European Union’s Horizon 2020 research and innovation programme
under the Marie Skłodowska-Curie grant agreement N°101034413. L.B. gratefully acknowledges
support from the European Research Council (ERC) under the Horizon Europe programme
(Calcifer; Starting Grant agreement N°101165631). J.B., M.R., S.M. and J.S.G.M have
been supported by CNES, focused on the preparation of the PLATO mission. Computations
with ESTER and TOP have made use of the HPC resources from the CALMIP supercomputing
centre (Grant 2023-P0107). This research made use of the numpy (Harris et al. 2020)
and matplotlib (Hunter 2007) Python software packages.'
article_number: A336
article_processing_charge: No
article_type: original
arxiv: 1
author:
- first_name: J. S.G.
full_name: Mombarg, J. S.G.
last_name: Mombarg
- first_name: V.
full_name: Vanlaer, V.
last_name: Vanlaer
- first_name: Srijan B
full_name: Das, Srijan B
id: 9ce7c423-dacf-11ed-8942-e09c6cb27149
last_name: Das
orcid: 0000-0003-0896-7972
- first_name: M.
full_name: Rieutord, M.
last_name: Rieutord
- first_name: C.
full_name: Aerts, C.
last_name: Aerts
- 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: S.
full_name: Mathis, S.
last_name: Mathis
- first_name: D. R.
full_name: Reese, D. R.
last_name: Reese
- first_name: J.
full_name: Ballot, J.
last_name: Ballot
citation:
ama: Mombarg JSG, Vanlaer V, Das SB, et al. Is a 1D perturbative method sufficient
for asteroseismic modelling of β Cephei pulsators? Implications for measurements
of rotation and internal magnetic fields. Astronomy & Astrophysics.
2025;704. doi:10.1051/0004-6361/202557247
apa: Mombarg, J. S. G., Vanlaer, V., Das, S. B., Rieutord, M., Aerts, C., Bugnet,
L. A., … Ballot, J. (2025). Is a 1D perturbative method sufficient for asteroseismic
modelling of β Cephei pulsators? Implications for measurements of rotation and
internal magnetic fields. Astronomy & Astrophysics. EDP Sciences. https://doi.org/10.1051/0004-6361/202557247
chicago: Mombarg, J. S.G., V. Vanlaer, Srijan B Das, M. Rieutord, C. Aerts, Lisa
Annabelle Bugnet, S. Mathis, D. R. Reese, and J. Ballot. “Is a 1D Perturbative
Method Sufficient for Asteroseismic Modelling of β Cephei Pulsators? Implications
for Measurements of Rotation and Internal Magnetic Fields.” Astronomy &
Astrophysics. EDP Sciences, 2025. https://doi.org/10.1051/0004-6361/202557247.
ieee: J. S. G. Mombarg et al., “Is a 1D perturbative method sufficient for
asteroseismic modelling of β Cephei pulsators? Implications for measurements of
rotation and internal magnetic fields,” Astronomy & Astrophysics, vol.
704. EDP Sciences, 2025.
ista: Mombarg JSG, Vanlaer V, Das SB, Rieutord M, Aerts C, Bugnet LA, Mathis S,
Reese DR, Ballot J. 2025. Is a 1D perturbative method sufficient for asteroseismic
modelling of β Cephei pulsators? Implications for measurements of rotation and
internal magnetic fields. Astronomy & Astrophysics. 704, A336.
mla: Mombarg, J. S. G., et al. “Is a 1D Perturbative Method Sufficient for Asteroseismic
Modelling of β Cephei Pulsators? Implications for Measurements of Rotation and
Internal Magnetic Fields.” Astronomy & Astrophysics, vol. 704, A336,
EDP Sciences, 2025, doi:10.1051/0004-6361/202557247.
short: J.S.G. Mombarg, V. Vanlaer, S.B. Das, M. Rieutord, C. Aerts, L.A. Bugnet,
S. Mathis, D.R. Reese, J. Ballot, Astronomy & Astrophysics 704 (2025).
date_created: 2026-01-04T23:01:35Z
date_published: 2025-12-19T00:00:00Z
date_updated: 2026-02-16T12:14:36Z
day: '19'
ddc:
- '520'
department:
- _id: LiBu
doi: 10.1051/0004-6361/202557247
ec_funded: 1
external_id:
arxiv:
- '2511.09617'
file:
- access_level: open_access
checksum: d838b4783920c43b7cc866e9cf08b383
content_type: application/pdf
creator: dernst
date_created: 2026-01-05T08:36:28Z
date_updated: 2026-01-05T08:36:28Z
file_id: '20937'
file_name: 2025_AstronomyAstrophysics_Mombarg.pdf
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success: 1
file_date_updated: 2026-01-05T08:36:28Z
has_accepted_license: '1'
intvolume: ' 704'
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- iso: eng
month: '12'
oa: 1
oa_version: Published Version
project:
- _id: fc2ed2f7-9c52-11eb-aca3-c01059dda49c
call_identifier: H2020
grant_number: '101034413'
name: 'IST-BRIDGE: International postdoctoral program'
- _id: 914d8549-16d5-11f0-9cad-bbe6324c93a9
grant_number: '101165631'
name: 'Unveiling the mysteries of stellar dynamics: a pioneering journey in magnetoasteroseismology'
publication: Astronomy & Astrophysics
publication_identifier:
eissn:
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issn:
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publication_status: published
publisher: EDP Sciences
quality_controlled: '1'
related_material:
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relation: research_data
status: public
scopus_import: '1'
status: public
title: Is a 1D perturbative method sufficient for asteroseismic modelling of β Cephei
pulsators? Implications for measurements of rotation and internal magnetic fields
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: 704
year: '2025'
...
---
OA_place: repository
OA_type: gold
_id: '20936'
abstract:
- lang: eng
text: "Supplementary material for Mombarg et al. (2025, A&A). Title: \"Is a 1D perturbative
method sufficient for asteroseismic modelling of \r\n~Cephei pulsators? Implications
for measurements of rotation and internal magnetic fields\"\r\n\r\nContent:\r\n-
Non-rotating ESTER models and associated .GSM models. (Xini = 0.71, Zini = 0.014,
vertical/horizonal viscosity 10^7 cm^2/s, vertical chemical diffusion 10^4 cm^2/s
for evolution model. More details on the ESTER models can be found in the ESTER
manual.\r\n\r\n- Rotational asymmetries computed with StORM and TOP in 1/d, and
the central m=0 frequency from TOP in 1/d. (all_A*_new.pkl)\r\n\r\n- Magnetic
asymmetries in 1/d for different obliquity angles between 0 and 90 deg for ZAMS
and MAMS model, for B_0 = 75 kG. *_nu key gives unperturbed mode frequencies,
*_npg the radial order (asym_dict.pkl, asym_dict_evol.pkl)"
article_processing_charge: No
author:
- first_name: Joey
full_name: Mombarg, Joey
last_name: Mombarg
- first_name: Vincent
full_name: Vanlaer, Vincent
last_name: Vanlaer
- first_name: Srijan B
full_name: Das, Srijan B
id: 9ce7c423-dacf-11ed-8942-e09c6cb27149
last_name: Das
orcid: 0000-0003-0896-7972
- first_name: Michel
full_name: Rieutord, Michel
last_name: Rieutord
- first_name: Conny
full_name: Aerts, Conny
last_name: Aerts
- 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: Stephane
full_name: Mathis, Stephane
last_name: Mathis
- first_name: Daniel
full_name: Reese, Daniel
last_name: Reese
- first_name: Jerome
full_name: Ballot, Jerome
last_name: Ballot
citation:
ama: Mombarg J, Vanlaer V, Das SB, et al. Is a 1D perturbative method sufficient
for asteroseismic modelling of β Cephei pulsators? 2025. doi:10.5281/ZENODO.17580178
apa: Mombarg, J., Vanlaer, V., Das, S. B., Rieutord, M., Aerts, C., Bugnet, L. A.,
… Ballot, J. (2025). Is a 1D perturbative method sufficient for asteroseismic
modelling of β Cephei pulsators? Zenodo. https://doi.org/10.5281/ZENODO.17580178
chicago: Mombarg, Joey, Vincent Vanlaer, Srijan B Das, Michel Rieutord, Conny Aerts,
Lisa Annabelle Bugnet, Stephane Mathis, Daniel Reese, and Jerome Ballot. “Is a
1D Perturbative Method Sufficient for Asteroseismic Modelling of β Cephei Pulsators?”
Zenodo, 2025. https://doi.org/10.5281/ZENODO.17580178.
ieee: J. Mombarg et al., “Is a 1D perturbative method sufficient for asteroseismic
modelling of β Cephei pulsators?” Zenodo, 2025.
ista: Mombarg J, Vanlaer V, Das SB, Rieutord M, Aerts C, Bugnet LA, Mathis S, Reese
D, Ballot J. 2025. Is a 1D perturbative method sufficient for asteroseismic modelling
of β Cephei pulsators?, Zenodo, 10.5281/ZENODO.17580178.
mla: Mombarg, Joey, et al. Is a 1D Perturbative Method Sufficient for Asteroseismic
Modelling of β Cephei Pulsators? Zenodo, 2025, doi:10.5281/ZENODO.17580178.
short: J. Mombarg, V. Vanlaer, S.B. Das, M. Rieutord, C. Aerts, L.A. Bugnet, S.
Mathis, D. Reese, J. Ballot, (2025).
date_created: 2026-01-05T08:39:33Z
date_published: 2025-11-11T00:00:00Z
date_updated: 2026-02-16T12:14:36Z
day: '11'
ddc:
- '520'
department:
- _id: LiBu
doi: 10.5281/ZENODO.17580178
main_file_link:
- open_access: '1'
url: https://doi.org/10.5281/zenodo.17580178
month: '11'
oa: 1
oa_version: Submitted Version
publisher: Zenodo
related_material:
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- id: '20931'
relation: used_in_publication
status: public
status: public
title: Is a 1D perturbative method sufficient for asteroseismic modelling of β Cephei
pulsators?
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: research_data_reference
user_id: 2DF688A6-F248-11E8-B48F-1D18A9856A87
year: '2025'
...
---
OA_place: publisher
OA_type: diamond
PlanS_conform: '1'
_id: '20350'
abstract:
- lang: eng
text: "Context. Rotation plays an important role in stellar evolution. However,
the mechanisms behind the transport of angular momentum in stars at various stages
of their evolution are not well understood. To improve our understanding of these
processes, it is necessary to measure and validate the internal rotation profiles
of stars across different stages of evolution and mass regimes.\r\nAims. Our aim
is to constrain the internal rotation profile of the 12-M⊙ β Cep pulsator HD 192575
from the observed pulsational multiplets and the asymmetries of their component
frequencies.\r\nMethods. We updated the forward asteroseismic modelling of HD
192575 based on new TESS observations. We inverted the rotation profile from the
symmetric part of the splittings and computed the multiplet asymmetries due to
the Coriolis force and stellar deformation, which we treated perturbatively. We
compared the computed asymmetries with the observed asymmetries.\r\nResults. Our
new forward asteroseismic modelling is in agreement with previous results but
with increased uncertainties, partially due to increased frequency precision,
which required us to relax certain constraints. Ambiguity in the mode identification
is the main source of the uncertainty, which also affects the inferred rotation
profiles. Almost all acceptable rotation profiles occur in the regime below 0.4
d−1 and favour weak radial differential rotation, with a ratio of core to envelope
rotation of less than 2. We find that the quality of the match between the observed
and theoretically predicted mode asymmetries is strongly dependent on the mode
identification and the internal structure of the star.\r\nConclusions. Our results
offer the first detailed rotation inversion for a β Cep pulsator. They show that
the rotation profile and the mode asymmetries provide a valuable tool for further
constraining the evolutionary properties of HD 192575, and in particular the details
of angular momentum transport in massive stars."
acknowledgement: "The authors appreciated the critical comments from the\r\nreferee,
which encouraged V.V. to embark upon a new code development\r\nsprint. V.V. gratefully
acknowledges support from the Research Foundation\r\nFlanders (FWO) under grant
agreement N◦1156923N (PhD Fellowship) and\r\nN\r\n◦K233724N (Travel grant). D.M.B.
gratefully acknowledges support from\r\nthe Research Foundation Flanders (FWO; grant
number: 1286521N), and UK\r\nResearch and Innovation (UKRI) in the form of a Frontier
Research grant under\r\nthe UK government’s ERC Horizon Europe funding guarantee
(SYMPHONY;\r\ngrant number: EP/Y031059/1), and a Royal Society University Research
Fellowship (URF; grant number: URF\\R1\\231631). S.B.D. acknowledges funding from\r\nthe
European Union’s Horizon 2020 research and innovation programme under\r\nthe Marie
Skłodowska-Curie grant agreement No 101034413. L.B. gratefully\r\nacknowledges support
from the European Research Council (ERC) under the\r\nHorizon Europe programme (Calcifer;
Starting Grant agreement N◦101165631).\r\nS.M. acknowledges support from the PLATO
CNES grant at CEA/DAp.C.A.\r\nacknowledges financial support from the Research Foundation
Flanders (FWO)\r\nunder grant K802922N (Sabbatical leave); she is grateful for the
kind hospitality\r\noffered by CEA/Saclay during her sabbatical work visits in the
spring of 2023.\r\nThe research leading to these results has received funding from
the European\r\nResearch Council (ERC) under the Horizon Europe programme (Synergy
Grant\r\nagreement N◦101071505: 4D-STAR). While funded by the European Union,\r\nviews
and opinions expressed are however those of the author(s) only and do\r\nnot necessarily
reflect those of the European Union or the European Research\r\nCouncil. Neither
the European Union nor the granting authority can be held\r\nresponsible for them.
The TESS data presented in this paper were obtained from\r\nthe Mikulski Archive
for Space Telescopes (MAST) at the Space Telescope Science Institute (STScI), which
is operated by the Association of Universities for\r\nResearch in Astronomy, Inc.,
under NASA contract NAS5-26555. Support to\r\nMAST for these data is provided by
the NASA Office of Space Science via grant\r\nNAG5-7584 and by other grants and
contracts. Funding for the TESS mission\r\nwas provided by the NASA Explorer Program."
article_number: A5
article_processing_charge: No
article_type: original
arxiv: 1
author:
- first_name: V.
full_name: Vanlaer, V.
last_name: Vanlaer
- first_name: D. M.
full_name: Bowman, D. M.
last_name: Bowman
- first_name: S.
full_name: Burssens, S.
last_name: Burssens
- first_name: Srijan B
full_name: Das, Srijan B
id: 9ce7c423-dacf-11ed-8942-e09c6cb27149
last_name: Das
orcid: 0000-0003-0896-7972
- 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: S.
full_name: Mathis, S.
last_name: Mathis
- first_name: C.
full_name: Aerts, C.
last_name: Aerts
citation:
ama: Vanlaer V, Bowman DM, Burssens S, et al. Interior rotation modelling of the
β Cep pulsator HD 192575 including multiplet asymmetries. Astronomy & Astrophysics.
2025;701. doi:10.1051/0004-6361/202452885
apa: Vanlaer, V., Bowman, D. M., Burssens, S., Das, S. B., Bugnet, L. A., Mathis,
S., & Aerts, C. (2025). Interior rotation modelling of the β Cep pulsator
HD 192575 including multiplet asymmetries. Astronomy & Astrophysics.
EDP Sciences. https://doi.org/10.1051/0004-6361/202452885
chicago: Vanlaer, V., D. M. Bowman, S. Burssens, Srijan B Das, Lisa Annabelle Bugnet,
S. Mathis, and C. Aerts. “Interior Rotation Modelling of the β Cep Pulsator HD
192575 Including Multiplet Asymmetries.” Astronomy & Astrophysics.
EDP Sciences, 2025. https://doi.org/10.1051/0004-6361/202452885.
ieee: V. Vanlaer et al., “Interior rotation modelling of the β Cep pulsator
HD 192575 including multiplet asymmetries,” Astronomy & Astrophysics,
vol. 701. EDP Sciences, 2025.
ista: Vanlaer V, Bowman DM, Burssens S, Das SB, Bugnet LA, Mathis S, Aerts C. 2025.
Interior rotation modelling of the β Cep pulsator HD 192575 including multiplet
asymmetries. Astronomy & Astrophysics. 701, A5.
mla: Vanlaer, V., et al. “Interior Rotation Modelling of the β Cep Pulsator HD 192575
Including Multiplet Asymmetries.” Astronomy & Astrophysics, vol. 701,
A5, EDP Sciences, 2025, doi:10.1051/0004-6361/202452885.
short: V. Vanlaer, D.M. Bowman, S. Burssens, S.B. Das, L.A. Bugnet, S. Mathis, C.
Aerts, Astronomy & Astrophysics 701 (2025).
date_created: 2025-09-14T22:01:32Z
date_published: 2025-09-01T00:00:00Z
date_updated: 2026-02-16T12:12:53Z
day: '01'
ddc:
- '520'
department:
- _id: LiBu
doi: 10.1051/0004-6361/202452885
ec_funded: 1
external_id:
arxiv:
- '2506.19948'
isi:
- '001561561200007'
file:
- access_level: open_access
checksum: 9ee9f34cf86305602d6cb3e07a1cc1a6
content_type: application/pdf
creator: dernst
date_created: 2025-09-15T06:58:09Z
date_updated: 2025-09-15T06:58:09Z
file_id: '20354'
file_name: 2025_AstronomyAstrophysics_Vanlaer.pdf
file_size: 3175077
relation: main_file
success: 1
file_date_updated: 2025-09-15T06:58:09Z
has_accepted_license: '1'
intvolume: ' 701'
isi: 1
language:
- iso: eng
month: '09'
oa: 1
oa_version: Published Version
project:
- _id: fc2ed2f7-9c52-11eb-aca3-c01059dda49c
call_identifier: H2020
grant_number: '101034413'
name: 'IST-BRIDGE: International postdoctoral program'
- _id: 914d8549-16d5-11f0-9cad-bbe6324c93a9
grant_number: '101165631'
name: 'Unveiling the mysteries of stellar dynamics: a pioneering journey in magnetoasteroseismology'
publication: Astronomy & Astrophysics
publication_identifier:
eissn:
- 1432-0746
issn:
- 0004-6361
publication_status: published
publisher: EDP Sciences
quality_controlled: '1'
scopus_import: '1'
status: public
title: Interior rotation modelling of the β Cep pulsator HD 192575 including multiplet
asymmetries
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: 701
year: '2025'
...
---
OA_type: closed access
_id: '17189'
abstract:
- lang: eng
text: Supergranules, which are solar flow features with a lateral scale of 30,000–40,000 km
and a lifetime of ~24 h, form a prominent component of the Sun’s convective spectrum.
However, their internal flows, which can be probed only by helioseismology, are
not well understood. We analyse dopplergrams recorded by the Solar Dynamics Observatory
satellite to identify and characterize ~23,000 supergranules. We find that the
vertical flows peak at a depth of ~10,000 km, and remain invariant over the full
range of lateral supergranular scales, contrary to numerical predictions. We also
infer that, within the local seismic resolution (≳5,000 km), downflows are ~40%
weaker than upflows, indicating an apparent mass-flux imbalance. This may imply
that the descending flows also comprise plumes, which maintain the mass balance
but are simply too small to be detected by seismic waves. These results challenge
the widely used mixing-length description of solar convection.
acknowledgement: "We thank F. J. Simons for the codes for computing Slepian functions,\r\nM.
Rempel and R. Cameron for their insights into solar convection, J.\r\nW. Lord for
the numerical simulations and J. Naranjo for his help with\r\nthe NYUAD NetDRMS
system. This research was carried out with the\r\nHigh Performance Computing resources
at NYUAD. The datasets were\r\nprepared in the data centre at the Center for Space
Science of NYUAD.\r\nThis research is based upon work supported by Tamkeen under
the\r\nNYUAD Research Institute (Grant Nos G1502 and CASS to C.S.H,\r\nS.H. and
K.R.S.). S.H. acknowledges funding from the Department\r\nof Atomic Energy, India.
K.R.S. and S.H. acknowledge support from\r\nthe Ofice of Sponsored Research of King
Abdullah University of\r\nScience and Technology (Award No. OSR-CRG2020-4342). S.B.D.\r\nacknowledges
funding from the Elisabeth H. and F. A. Dahlen Award\r\n2022 by the Department of
Geosciences, Princeton University. S.B.D.\r\nalso acknowledges funding from the
European Union’s Horizon 2020\r\nresearch and innovation programme under a Marie
Skłodowska-Curie\r\ngrant (Grant Agreement No. 101034413). Some data products were\r\nprocessed
and downloaded from the German Data Center for SDO,\r\nwhich is funded by the German
Aerospace Center (DLR Grant No.\r\n500L1701)."
article_processing_charge: No
article_type: original
author:
- first_name: Chris S.
full_name: Hanson, Chris S.
last_name: Hanson
- first_name: Srijan B
full_name: Das, Srijan B
id: 9ce7c423-dacf-11ed-8942-e09c6cb27149
last_name: Das
orcid: 0000-0003-0896-7972
- first_name: Prasad
full_name: Mani, Prasad
last_name: Mani
- first_name: Shravan
full_name: Hanasoge, Shravan
last_name: Hanasoge
- first_name: Katepalli R.
full_name: Sreenivasan, Katepalli R.
last_name: Sreenivasan
citation:
ama: Hanson CS, Das SB, Mani P, Hanasoge S, Sreenivasan KR. Supergranular-scale
solar convection not explained by mixing-length theory. Nature Astronomy.
2024;8:1088-1101. doi:10.1038/s41550-024-02304-w
apa: Hanson, C. S., Das, S. B., Mani, P., Hanasoge, S., & Sreenivasan, K. R.
(2024). Supergranular-scale solar convection not explained by mixing-length theory.
Nature Astronomy. Springer Nature. https://doi.org/10.1038/s41550-024-02304-w
chicago: Hanson, Chris S., Srijan B Das, Prasad Mani, Shravan Hanasoge, and Katepalli
R. Sreenivasan. “Supergranular-Scale Solar Convection Not Explained by Mixing-Length
Theory.” Nature Astronomy. Springer Nature, 2024. https://doi.org/10.1038/s41550-024-02304-w.
ieee: C. S. Hanson, S. B. Das, P. Mani, S. Hanasoge, and K. R. Sreenivasan, “Supergranular-scale
solar convection not explained by mixing-length theory,” Nature Astronomy,
vol. 8. Springer Nature, pp. 1088–1101, 2024.
ista: Hanson CS, Das SB, Mani P, Hanasoge S, Sreenivasan KR. 2024. Supergranular-scale
solar convection not explained by mixing-length theory. Nature Astronomy. 8, 1088–1101.
mla: Hanson, Chris S., et al. “Supergranular-Scale Solar Convection Not Explained
by Mixing-Length Theory.” Nature Astronomy, vol. 8, Springer Nature, 2024,
pp. 1088–101, doi:10.1038/s41550-024-02304-w.
short: C.S. Hanson, S.B. Das, P. Mani, S. Hanasoge, K.R. Sreenivasan, Nature Astronomy
8 (2024) 1088–1101.
date_created: 2024-06-30T22:01:05Z
date_published: 2024-09-01T00:00:00Z
date_updated: 2025-09-08T08:04:56Z
day: '01'
department:
- _id: LiBu
doi: 10.1038/s41550-024-02304-w
ec_funded: 1
external_id:
isi:
- '001254181700001'
intvolume: ' 8'
isi: 1
language:
- iso: eng
month: '09'
oa_version: None
page: 1088-1101
project:
- _id: fc2ed2f7-9c52-11eb-aca3-c01059dda49c
call_identifier: H2020
grant_number: '101034413'
name: 'IST-BRIDGE: International postdoctoral program'
publication: Nature Astronomy
publication_identifier:
eissn:
- 2397-3366
publication_status: published
publisher: Springer Nature
quality_controlled: '1'
scopus_import: '1'
status: public
title: Supergranular-scale solar convection not explained by mixing-length theory
type: journal_article
user_id: 317138e5-6ab7-11ef-aa6d-ffef3953e345
volume: 8
year: '2024'
...
---
DOAJ_listed: '1'
_id: '17326'
abstract:
- lang: eng
text: Magnetic fields in the stellar interiors are key candidates to explain observed
core rotation rates inside solar-like stars along their evolution. Recently, asteroseismic
estimates of radial magnetic field amplitudes near the hydrogen-burning shell
(H-shell) inside about 24 red giants (RGs) have been obtained by measuring frequency
splittings from their power spectra. Using general Lorentz-stress (magnetic) kernels,
we investigated the potential for detectability of near-surface magnetism in a
1.3 M⊙ star of supersolar metallicity as it evolves from a mid subgiant to a late
subgiant into an RG. Based on these sensitivity kernels, we decompose an RG into
three zones—deep core, H-shell, and near-surface. The subgiants instead required
decomposition into an inner core, an outer core, and a near-surface layer. Additionally,
we find that for a low-frequency g-dominated dipolar mode in the presence of a
typical stable magnetic field, ∼25% of the frequency shift comes from the H-shell
and the remaining from deeper layers. The ratio of the subsurface tangential field
to the radial field in the H-burning shell decides if subsurface fields may be
potentially detectable. For p-dominated dipole modes close to vmax, this ratio
is around two orders of magnitude smaller in subgiant phases than the corresponding
RG. Further, with the availability of magnetic kernels, we propose lower limits
of field strengths in crucial layers in our stellar model during its evolutionary
phases. The theoretical prescription outlined here provides the first formal way
to devise inverse problems for stellar magnetism and can be seamlessly employed
for slow rotators.
acknowledgement: "This project has received funding from the European Union's Horizon
2020 research and innovation program under the Marie Skłodowska-Curie grant agreement
No. 101034413. S.\r\nB.D. acknowledges Prof. Jeroen Tromp at Princeton University
for supporting a part of this work. S.M.H., S.B., and S.P. acknowledge support from
the Department of Atomic Energy,\r\nGovernment of India, under Project Identification
No. RTI 4002. The authors would like to thank the reviewer(s) and data editor for
their constructive comments and suggestions. The\r\ngeneration of the stellar models
was done using the Modules for Experiments in Stellar Astrophysics (MESA Paxton
et al. 2011, 2013, 2015, 2018, 2019; we have used MESA version\r\nr22.05.1 for RG
and r23.05.1 for SG models, MESA-SDK version x86_64-linux-22.6.1). The eigenfrequencies
and eigenfunctions for this model were calculated using the GYRE\r\n(Townsend &
Teitler 2013) code. The code to calculate the kernels and the splittings has been
written completely in Python 3.8.16."
article_number: '42'
article_processing_charge: Yes
article_type: original
arxiv: 1
author:
- first_name: Shatanik
full_name: Bhattacharya, Shatanik
last_name: Bhattacharya
- first_name: Srijan B
full_name: Das, Srijan B
id: 9ce7c423-dacf-11ed-8942-e09c6cb27149
last_name: Das
orcid: 0000-0003-0896-7972
- 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: Subrata
full_name: Panda, Subrata
last_name: Panda
- first_name: Shravan M.
full_name: Hanasoge, Shravan M.
last_name: Hanasoge
citation:
ama: Bhattacharya S, Das SB, Bugnet LA, Panda S, Hanasoge SM. Detectability of axisymmetric
magnetic fields from the core to the surface of oscillating post-main-sequence
stars. Astrophysical Journal. 2024;970(1). doi:10.3847/1538-4357/ad4708
apa: Bhattacharya, S., Das, S. B., Bugnet, L. A., Panda, S., & Hanasoge, S.
M. (2024). Detectability of axisymmetric magnetic fields from the core to the
surface of oscillating post-main-sequence stars. Astrophysical Journal.
IOP Publishing. https://doi.org/10.3847/1538-4357/ad4708
chicago: Bhattacharya, Shatanik, Srijan B Das, Lisa Annabelle Bugnet, Subrata Panda,
and Shravan M. Hanasoge. “Detectability of Axisymmetric Magnetic Fields from the
Core to the Surface of Oscillating Post-Main-Sequence Stars.” Astrophysical
Journal. IOP Publishing, 2024. https://doi.org/10.3847/1538-4357/ad4708.
ieee: S. Bhattacharya, S. B. Das, L. A. Bugnet, S. Panda, and S. M. Hanasoge, “Detectability
of axisymmetric magnetic fields from the core to the surface of oscillating post-main-sequence
stars,” Astrophysical Journal, vol. 970, no. 1. IOP Publishing, 2024.
ista: Bhattacharya S, Das SB, Bugnet LA, Panda S, Hanasoge SM. 2024. Detectability
of axisymmetric magnetic fields from the core to the surface of oscillating post-main-sequence
stars. Astrophysical Journal. 970(1), 42.
mla: Bhattacharya, Shatanik, et al. “Detectability of Axisymmetric Magnetic Fields
from the Core to the Surface of Oscillating Post-Main-Sequence Stars.” Astrophysical
Journal, vol. 970, no. 1, 42, IOP Publishing, 2024, doi:10.3847/1538-4357/ad4708.
short: S. Bhattacharya, S.B. Das, L.A. Bugnet, S. Panda, S.M. Hanasoge, Astrophysical
Journal 970 (2024).
date_created: 2024-07-28T22:01:09Z
date_published: 2024-07-15T00:00:00Z
date_updated: 2025-09-08T08:42:20Z
day: '15'
ddc:
- '520'
department:
- _id: LiBu
doi: 10.3847/1538-4357/ad4708
ec_funded: 1
external_id:
arxiv:
- '2404.17167'
isi:
- '001270972500001'
file:
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checksum: acb42a87deecbc9228fbbe6a48a37ec6
content_type: application/pdf
creator: dernst
date_created: 2024-07-29T11:02:48Z
date_updated: 2024-07-29T11:02:48Z
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file_name: 2024_AstrophysicalJourn_Bhattacharya.pdf
file_size: 3912290
relation: main_file
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intvolume: ' 970'
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issue: '1'
language:
- iso: eng
month: '07'
oa: 1
oa_version: Published Version
project:
- _id: fc2ed2f7-9c52-11eb-aca3-c01059dda49c
call_identifier: H2020
grant_number: '101034413'
name: 'IST-BRIDGE: International postdoctoral program'
publication: Astrophysical Journal
publication_identifier:
eissn:
- 1538-4357
issn:
- 0004-637X
publication_status: published
publisher: IOP Publishing
quality_controlled: '1'
scopus_import: '1'
status: public
title: Detectability of axisymmetric magnetic fields from the core to the surface
of oscillating post-main-sequence stars
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: 317138e5-6ab7-11ef-aa6d-ffef3953e345
volume: 970
year: '2024'
...
---
OA_place: publisher
OA_type: hybrid
_id: '18528'
abstract:
- lang: eng
text: The recent measurement of magnetic field strength inside the radiative interior
of red giant stars has opened the way toward full 3D characterization of the geometry
of stable large-scale magnetic fields. However, current measurements, which are
limited to dipolar (ℓ = 1) mixed modes, do not properly constrain the topology
of magnetic fields due to degeneracies on the observed magnetic field signature
on such ℓ = 1 mode frequencies. Efforts focused toward unambiguous detections
of magnetic field configurations are now key to better understand angular momentum
transport in stars. We investigated the detectability of complex magnetic field
topologies (such as the ones observed at the surface of stars with a radiative
envelope with spectropolarimetry) inside the radiative interior of red giants.
We focused on a field composed of a combination of a dipole and a quadrupole (quadrudipole)
and on an offset field. We explored the potential of probing such magnetic field
topologies from a combined measurement of magnetic signatures on ℓ = 1 and quadrupolar
(ℓ = 2) mixed mode oscillation frequencies. We first derived the asymptotic theoretical
formalism for computing the asymmetric signature in the frequency pattern for
ℓ = 2 modes due to a quadrudipole magnetic field. To access asymmetry parameters
for more complex magnetic field topologies, we numerically performed a grid search
over the parameter space to map the degeneracy of the signatures of given topologies.
We demonstrate the crucial role played by ℓ = 2 mixed modes in accessing internal
magnetic fields with a quadrupolar component. The degeneracy of the quadrudipole
compared to pure dipolar fields is lifted when considering magnetic asymmetries
in both ℓ = 1 and ℓ = 2 mode frequencies. In addition to the analytical derivation
for the quadrudipole, we present the prospect for complex magnetic field inversions
using magnetic sensitivity kernels from standard perturbation analysis for forward
modeling. Using this method, we explored the detectability of offset magnetic
fields from ℓ = 1 and ℓ = 2 frequencies and demonstrate that offset fields may
be mistaken for weak and centered magnetic fields, resulting in underestimating
the magnetic field strength in stellar cores. We emphasize the need to characterize
ℓ = 2 mixed-mode frequencies, (along with the currently characterized ℓ = 1 mixed
modes), to unveil the higher-order components of the geometry of buried magnetic
fields and to better constrain angular momentum transport inside stars.
acknowledgement: The authors thank S. Mathis, L. Barrault, S. Torres, A. Cristea,
and K. M. Smith for very useful discussions. This project has received funding from
the European Union’s Horizon 2020 research and innovation programme under the Marie
Skłodowska-Curíe grant agreement No 101034413. The authors thank the anonymous referee
for valuable comments and suggestions to improve the manuscript.
article_number: A217
article_processing_charge: No
article_type: original
arxiv: 1
author:
- first_name: Srijan B
full_name: Das, Srijan B
id: 9ce7c423-dacf-11ed-8942-e09c6cb27149
last_name: Das
orcid: 0000-0003-0896-7972
- 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
citation:
ama: Das SB, Einramhof L, Bugnet LA. Unveiling complex magnetic field configurations
in red giant stars. Astronomy & Astrophysics. 2024;690. doi:10.1051/0004-6361/202450918
apa: Das, S. B., Einramhof, L., & Bugnet, L. A. (2024). Unveiling complex magnetic
field configurations in red giant stars. Astronomy & Astrophysics.
EDP Sciences. https://doi.org/10.1051/0004-6361/202450918
chicago: Das, Srijan B, Lukas Einramhof, and Lisa Annabelle Bugnet. “Unveiling Complex
Magnetic Field Configurations in Red Giant Stars.” Astronomy & Astrophysics.
EDP Sciences, 2024. https://doi.org/10.1051/0004-6361/202450918.
ieee: S. B. Das, L. Einramhof, and L. A. Bugnet, “Unveiling complex magnetic field
configurations in red giant stars,” Astronomy & Astrophysics, vol.
690. EDP Sciences, 2024.
ista: Das SB, Einramhof L, Bugnet LA. 2024. Unveiling complex magnetic field configurations
in red giant stars. Astronomy & Astrophysics. 690, A217.
mla: Das, Srijan B., et al. “Unveiling Complex Magnetic Field Configurations in
Red Giant Stars.” Astronomy & Astrophysics, vol. 690, A217, EDP Sciences,
2024, doi:10.1051/0004-6361/202450918.
short: S.B. Das, L. Einramhof, L.A. Bugnet, Astronomy & Astrophysics 690 (2024).
corr_author: '1'
das_tickbox: '1'
date_created: 2024-11-10T23:02:00Z
date_published: 2024-10-01T00:00:00Z
date_updated: 2026-07-08T06:44:58Z
day: '01'
ddc:
- '520'
department:
- _id: LiBu
doi: 10.1051/0004-6361/202450918
ec_funded: 1
external_id:
arxiv:
- '2405.20133'
isi:
- '001336485200015'
file:
- access_level: open_access
checksum: d43bbe6ed8ce4512e65e2d0d87070cf6
content_type: application/pdf
creator: dernst
date_created: 2024-11-11T09:01:11Z
date_updated: 2024-11-11T09:01:11Z
file_id: '18534'
file_name: 2024_AstronomyAstrophysics_Das.pdf
file_size: 5306256
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file_date_updated: 2024-11-11T09:01:11Z
has_accepted_license: '1'
intvolume: ' 690'
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language:
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month: '10'
oa: 1
oa_version: Published Version
project:
- _id: fc2ed2f7-9c52-11eb-aca3-c01059dda49c
call_identifier: H2020
grant_number: '101034413'
name: 'IST-BRIDGE: International postdoctoral program'
publication: Astronomy & Astrophysics
publication_identifier:
eissn:
- 1432-0746
issn:
- 0004-6361
publication_status: published
publisher: EDP Sciences
quality_controlled: '1'
scopus_import: '1'
status: public
title: Unveiling complex magnetic field configurations in red giant stars
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: 690
year: '2024'
...