Asteroseismology applies seismology to stars. On Earth, seismologists measure motions and waves in the crust and mantle to learn about their structure and composition. In the Sun and other stars, asteroseismologists measure changes in the brightness and velocity to learn about the structure of the atmosphere and interior of a star. Because the changes are small (velocities of meters per second), CfA scientists use special purpose instruments to study the structure of nearby bright stars.
Sylvain Korzennik, Robert Noyes, Dimitar Sasselov