Magnetic signatures in merger products
4 affiliations
- 1Institute of Science and Technology Austria (ISTA)
- 2Instituto de Astrofísica de Canarias
- 3Departamento de Astrofísica, Universidad de La Laguna
- 4Université Paris Cité, Université Paris-Saclay, CEA, CNRS, AIM
Abstract
Asteroseismic estimates of the magnetic field strength in the radiative interior of red giant stars depend strongly on the internal stellar structure derived from models. Since red-giant-branch merger products have been shown to be able to possess a different core structure than single stars of the same mass, we investigated how a mass-gain history influences our estimates of an internal magnetic field strength. We constructed stellar models with and without a mass-gain event after the onset of the red giant branch evolutionary phase with masses of 1.1 M ⊙ ≤ M ≤ 2 M ⊙ . First, by assuming a weak magnetic field, we investigated the influence of a mass-gain event on the global sensitivity of the oscillation frequencies to the magnetic field. We find that mass-gain models can be several times more sensitive to the field than single-star models of identical total mass at masses above 1.6 M ⊙ . Therefore, considering a mass-gain evolutionary history for merger candidates allows a significant correction to the magnetic field strength. In the presence of strong magnetic fields, we also show that the critical field strength needed to suppress mixed dipole modes is significantly lower if a mass-gain event has occurred (for stars with masses of M ≳ 1.6 M ⊙ ). The massive end of the suppressed stars’ distribution is therefore strongly favored by a merger origin. We conclude that properly constraining the stellar evolutionary history is essential when aiming to constrain internal field strength estimates from asteroseismic observations.
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BibTeX
@article{muntean2026magnetic,
title = {{Magnetic signatures in merger products}},
author = {N. Muntean and L. Bugnet and L. Buchele and D. Dutta and L. Einramhof and P. G. Beck and L. Barrault and B. Liagre},
journal = {Astronomy \& Astrophysics},
year = {2026},
month = oct,
doi = {10.1051/0004-6361/202661734},
url = {https://www.aanda.org/10.1051/0004-6361/202661734},
note = {CC BY 4.0},
}
RIS
TY - JOUR
TI - Magnetic signatures in merger products
AU - N. Muntean
AU - L. Bugnet
AU - L. Buchele
AU - D. Dutta
AU - L. Einramhof
AU - P. G. Beck
AU - L. Barrault
AU - B. Liagre
PY - 2026
DA - 2026/10/28
JO - Astronomy & Astrophysics
DO - 10.1051/0004-6361/202661734
UR - https://www.aanda.org/10.1051/0004-6361/202661734
AB - Asteroseismic estimates of the magnetic field strength in the radiative interior of red giant stars depend strongly on the internal stellar structure derived from models. Since red-giant-branch merger products have been shown to be able to possess a different core structure than single stars of the same mass, we investigated how a mass-gain history influences our estimates of an internal magnetic field strength. We constructed stellar models with and without a mass-gain event after the onset of the red giant branch evolutionary phase with masses of 1.1 M ⊙ ≤ M ≤ 2 M ⊙ . First, by assuming a weak magnetic field, we investigated the influence of a mass-gain event on the global sensitivity of the oscillation frequencies to the magnetic field. We find that mass-gain models can be several times more sensitive to the field than single-star models of identical total mass at masses above 1.6 M ⊙ . Therefore, considering a mass-gain evolutionary history for merger candidates allows a significant correction to the magnetic field strength. In the presence of strong magnetic fields, we also show that the critical field strength needed to suppress mixed dipole modes is significantly lower if a mass-gain event has occurred (for stars with masses of M ≳ 1.6 M ⊙ ). The massive end of the suppressed stars’ distribution is therefore strongly favored by a merger origin. We conclude that properly constraining the stellar evolutionary history is essential when aiming to constrain internal field strength estimates from asteroseismic observations.
SN - 0004-6361
SN - 1432-0746
ER -