Novel seismic probes: The magnetic field measurement in red giants and the Sun

One of the most successful novel probes in asteroseismology in recent years is the one to measure the internal magnetic field in red giants from their frequencies. The result has a significant impact in not only asteroseismology, but also stellar physics in general. On the other hand, it was once claimed in helioseismology that the magnetic field in the subsurface layer is responsible for the change in oscillation frequencies along with the activity of the Sun. However, the situation then became complicated because the predicted change in the field strength turned out to be much larger than actually observed at the photosphere. The purpose of this presentation is to make it clear why the two cases, one for red giants and the other for the Sun, are so different from each other.