  The study of stellar oscillations - asteroseismology - has revolutionized our
understanding of the physical properties of the Sun, and similar potential for
other stars has been demonstrated in recent years. In particular, asteroseismic
studies can constrain the stellar size, temperature and composition, which are
important parameters to our understanding of planetary structure and evolution.
This makes asteroseismology a very powerful tool to complement planetary
transits. As an example, the transit measurement alone does not give the radius
of the planet unless the radius of the host star is known, which again requires
a known distance to the system. Transit measurements will therefore often
require additional measurements to establish the radius of the planet. With
asteroseismology we can determine the radius of a star to very high precision
(2-3%) using only the photometric transit measurements. This will be very
valuable for a mission such as Kepler, which will produce photometric time
series of very high quality.
