Helioseismology

Summary

Helioseismology is the study of the interior of the Sun through its oscillations. The surface of the Sun moves in millions of pulsation modes, mainly acoustic p modes with periods near five minutes. Their measured frequencies are inverted to give the sound speed, the density and the rotation rate as functions of depth. It is the solar case of asteroseismology, and the most precise one, because individual modes of high degree can be resolved on the solar disk.