Magnetic signatures in merger products
Year: 2026
Type: article
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.
Source: Astronomy and Astrophysics
Institutions: Institute of Science and Technology Austria, Universidad de La Laguna, Instituto de Astrofísica de Canarias, Centre National de la Recherche Scientifique, Université Paris Cité, Commissariat à l'Énergie Atomique et aux Énergies Alternatives, Université Paris-Saclay, CEA Paris-Saclay - Etablissement de Saclay
Language: English
Subfield: Astronomy and Astrophysics
Field: Physics and Astronomy
Domain: Physical Sciences
Open Access status: gold
Estimated APC paid: $1,865
Awards: G1078143841, G1105844351, G1175115578, G1272900390, G2257393230, G2262748287, G24120701, G2601397997, G294895050, G300979063, G3480869486, G3681454997, G4042783231, G4111202696, G425668148, G464105488, G491712853, G5049803760, G5080475149, G5195188938, G5635532810, G593054264, G7084143925, G7395345766, Unveiling the mysteries of stellar dynamics: a pioneering journey in magnetoasteroseismology, G7805626310, G7863371703, G8185622842, G8497050386, G8667377315, G8903162199
OpenAlex ID: W7212033450