Dipole modes with depressed amplitudes in red giants are mixed modes

Understand

Seismic observations have shown that a number of evolved stars exhibit low-amplitude dipole modes, which are referred to as depressed modes.

• Recently, these low amplitudes have been attributed to the presence of a strong magnetic field in the stellar core of those stars.
• We intend to study the properties of depressed modes in evolved stars, which is a necessary condition before concluding on the physical nature of the mechanism responsible for the reduction of the dipole mode amplitudes.
• We perform a thorough characterization of the global seismic parameters of depressed dipole modes and show that these modes have a mixed character.