---
DOAJ_listed: '1'
OA_place: publisher
OA_type: gold
PlanS_conform: '1'
_id: '22262'
abstract:
- lang: eng
  text: Mixed modes are observed in many low-mass evolved stars. They provide information
    about core rotation rates of these stars, which are lower than predicted by stellar
    evolution models. The mixed modes themselves have been invoked as an angular momentum
    (AM) transport mechanism, but estimating their transport efficiency requires knowledge
    of their amplitudes. We constrain, for the first time, the mixed-mode amplitudes
    in 2D hydrodynamical simulations of a 1.3M⊙ red giant using the code MUSIC. We
    perform two simulations with outer radial truncations at fractional radii ro/r⋆
    = 0.90 and 0.98. We compare the modes in the simulation with those found using
    both GYRE and a Dedalus eigenvalue solver. Excellent frequency agreement is found
    for all p-dominated modes, with minor discrepancies for g-dominated modes, especially
    in the frequency range [60, 240] μHz. We find excellent eigenfunction agreement
    for all modes except those in this frequency range. According to empirical predictions,
    the largest kinetic energies are located around Vmax= 312.μHz, but in both simulations,
    the modes with frequencies of ν < 50 μHz have the largest kinetic energies. In
    the simulation with r/r⋆ = 0.98, the simulated modes have extrapolated surface
    velocities comparable to the empirical predictions, with the highest surface velocities
    in a bell-shaped curve peaking around ν = 700 μHz. The extrapolated surface velocities
    of the low-frequency modes are small and thus hard to observe, but their large
    kinetic energies deeper in the interior could significantly impact AM transport,
    which has not yet been investigated.
acknowledgement: 'We would like to thank the referee for their careful reading of
  the manuscript and their constructive comments that helped improve the paper. N.B.V.
  would like to thank K. Belkacem and J. Philidet for helpful discussions. N.B.V.
  is supported by STFC grant ST/Y002164/1. A.L.S. acknowledges support from the European
  Research Council (ERC) under the Horizon Europe program (Synergy grant agreement
  101071505: 4D-STAR) from the CNES SOHO-GOLF and PLATO grants at CEA-DAp, and from
  ATPS (CNRS/INSU). Part of this work was supported by the ERC grant No. 787361-COBOM.
  R.H.D.T. acknowledges support from NASA grants 80NSSC24K0895 and 80NSSC23K1517,
  and NSF grant 2407636. A.L. is supported by ERC Starting Grant 101165631 (“Calcifer”).
  The authors would like to acknowledge the use of the University of Exeter High-Performance
  Computing (HPC) facility, ISCA, in carrying out this work. This work used the DiRAC
  Memory Intensive service (Cosma8) at Durham University, managed by the Institute
  for Computational Cosmology, and the DiRAC Data Intensive service (DIaL3) at the
  University of Leicester, managed by the University of Leicester Research Computing
  Service. These facilities are managed on behalf of the STFC DiRAC HPC (www.dirac.ac.uk).
  The DiRAC services at Durham and Leicester were funded by BEIS, UKRI, and STFC capital
  funding, and STFC operations grants. The service at Durham received funding from
  Durham University. DiRAC is part of the UKRI Digital Research Infrastructure.'
article_number: '154'
article_processing_charge: Yes
article_type: original
arxiv: 1
author:
- first_name: Nils B.
  full_name: De Vries, Nils B.
  last_name: De Vries
- first_name: Arthur
  full_name: Le Saux, Arthur
  last_name: Le Saux
- first_name: Isabelle
  full_name: Baraffe, Isabelle
  last_name: Baraffe
- first_name: Thomas
  full_name: Guillet, Thomas
  last_name: Guillet
- first_name: Richard H.D.
  full_name: Townsend, Richard H.D.
  last_name: Townsend
- first_name: Armand
  full_name: Leclerc, Armand
  id: 2a1fb1fc-f373-11ef-901a-87cee43a1217
  last_name: Leclerc
- first_name: Adrien
  full_name: Morison, Adrien
  last_name: Morison
citation:
  ama: De Vries NB, Le Saux A, Baraffe I, et al. Revealing mixed modes in compressible
    hydrodynamical simulations of red giant stars. <i>The Astrophysical Journal</i>.
    2026;1005(2). doi:<a href="https://doi.org/10.3847/1538-4357/ae7a3c">10.3847/1538-4357/ae7a3c</a>
  apa: De Vries, N. B., Le Saux, A., Baraffe, I., Guillet, T., Townsend, R. H. D.,
    Leclerc, A., &#38; Morison, A. (2026). Revealing mixed modes in compressible hydrodynamical
    simulations of red giant stars. <i>The Astrophysical Journal</i>. IOP Publishing.
    <a href="https://doi.org/10.3847/1538-4357/ae7a3c">https://doi.org/10.3847/1538-4357/ae7a3c</a>
  chicago: De Vries, Nils B., Arthur Le Saux, Isabelle Baraffe, Thomas Guillet, Richard
    H.D. Townsend, Armand Leclerc, and Adrien Morison. “Revealing Mixed Modes in Compressible
    Hydrodynamical Simulations of Red Giant Stars.” <i>The Astrophysical Journal</i>.
    IOP Publishing, 2026. <a href="https://doi.org/10.3847/1538-4357/ae7a3c">https://doi.org/10.3847/1538-4357/ae7a3c</a>.
  ieee: N. B. De Vries <i>et al.</i>, “Revealing mixed modes in compressible hydrodynamical
    simulations of red giant stars,” <i>The Astrophysical Journal</i>, vol. 1005,
    no. 2. IOP Publishing, 2026.
  ista: De Vries NB, Le Saux A, Baraffe I, Guillet T, Townsend RHD, Leclerc A, Morison
    A. 2026. Revealing mixed modes in compressible hydrodynamical simulations of red
    giant stars. The Astrophysical Journal. 1005(2), 154.
  mla: De Vries, Nils B., et al. “Revealing Mixed Modes in Compressible Hydrodynamical
    Simulations of Red Giant Stars.” <i>The Astrophysical Journal</i>, vol. 1005,
    no. 2, 154, IOP Publishing, 2026, doi:<a href="https://doi.org/10.3847/1538-4357/ae7a3c">10.3847/1538-4357/ae7a3c</a>.
  short: N.B. De Vries, A. Le Saux, I. Baraffe, T. Guillet, R.H.D. Townsend, A. Leclerc,
    A. Morison, The Astrophysical Journal 1005 (2026).
das_tickbox: '1'
dataavailabilitystatement: The kinetic energies and surface velocities shown in Figure
  4, as well as the underlying spectral data of this work, can be found in a Zenodo
  repository at doi:10.5281/zenodo.18661976.
date_created: 2026-07-12T22:02:17Z
date_published: 2026-07-10T00:00:00Z
date_updated: 2026-07-13T08:16:25Z
day: '10'
ddc:
- '520'
department:
- _id: LiBu
doi: 10.3847/1538-4357/ae7a3c
external_id:
  arxiv:
  - '2606.07125'
file:
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has_accepted_license: '1'
intvolume: '      1005'
issue: '2'
keyword:
- Stellar physics
- Stellar interiors
- Asteroseismology
- Stellar oscillations
- Hydrodynamical simulations
language:
- iso: eng
month: '07'
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'
publication: The Astrophysical Journal
publication_identifier:
  eissn:
  - 1538-4357
  issn:
  - 0004-637X
publication_status: published
publisher: IOP Publishing
quality_controlled: '1'
researchdata_availability: yes
scopus_import: '1'
status: public
supplementarymaterial: yes
title: Revealing mixed modes in compressible hydrodynamical simulations of 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: 1005
year: '2026'
...