Detecting magnetic fields in γ Doradus stars with asteroseismology

Magnetic fields have recently been measured in the cores of red giant stars through their effects on stellar oscillation frequencies. Beyond red giants, seismic signatures of magnetic fields can be sought in other pulsating stars. γ Doradus stars are excellent candidates, as they oscillate in the low-frequency range, which is most affected by magnetic fields. Gravity modes have been identified in more than 600 γ Doradus stars observed by Kepler and in approximately 60 γ Doradus stars observed by TESS. These modes are sensitive to the radiative layers just above the convective core, where magnetic fields are most likely generated by a convective dynamo. Moreover, these stars are progenitors of red giants, and detecting magnetic fields in γ Doradus stars would provide new constraints on the origin of magnetic fields in red giants. The theoretical impact of magnetic fields on these modes has been recently studied for a general magnetic field configuration. In Lignières et al. (2024), we proposed a seismic diagnostic combining ℓ=1 and ℓ=2 sectoral prograde modes (also called Kelvin modes). We identified a γ Doradus star exhibiting the expected signature of a magnetic field. In this talk, I will present this intriguing result, paying particular attention to other phenomena (such as glitches or dips) that could mimic this signature.