The way in which pulsations occur in a star. It may be described in terms of either the frequency of pulsation, or the physical motions of the star's surface. Pulsation at the lowest (forcing) frequency is known as the fundamental mode; at twice the frequency, the first overtone mode; and so on. A star may pulsate either with approximately spherical symmetry (radial pulsation), or as a series of waves running across the surface (non-radial pulsation). Pulsation may occur in a single mode or in multiple modes, depending on the type of star.
Subjects: Astronomy and Astrophysics.