A rocky core is postulated to comply with the common formation scenario of the giant planets. The uncertainty on the location of the boundaries of these components, as the mixing ratio of hydrogen to helium, offers a set of many possible models. Whether or not a rocky core is present at the center of the planet, of which size, is a question which has implications on the composition in solid components of the solar nebula around 5 AU and beyond from the primitive Sun. Another source of information is needed to select among the numerous models of Jupiter's interior which are possible. That can be provided only by a seismological study of the planet, as is done for the Earth or for the Sun.
Seismic waves propagate through a body at the sound velocity.
This velocity is determined by the density of the medium in which the seismic waves travel. For the Earth the acoustic waves are generated by earthquakes. In the Sun, the convective motions of the upper layers of the atmosphere excite continuously resonances of the whole solar sphere, at specific frequencies, which correspond to trapped waves. It should be the same for Jupiter since the giant planet contains a source of internal heat, which must create convection in the upper layers of its atmosphere. That is the reason for which a seismic study of Jupiter, first target of this study, has been undertaken.