Asteroseismology of exoplanets-host stars

Studying the internal structure of exoplanets-host stars compared to that of similar stars without detected planets is particularly important for the understanding of planetary formation. The observed overmetallicity of stars around which planets have been detected may be a hint in that respect. In this framework, asteroseismic studies represent an excellent tool to determine the structural differences between stars with and without detected planets. After a general discussion on this subject, I present the special cases of three different stars: $\mu$ Arae which has been observed with the HARPS spectrograph in June 2004, $\iota$ Horologii, that we have studied in detail and will be observed with HARPS in November 2006, and finally HD 52265, one of the main targets of the COROT mission, an exoplanets-host star which will be observed with the COROT satellite during five consecutive months.