Asteroseismology is an area of astrophysics that has existed for around twenty years, but which has blossomed over the last two or three years thanks to two satellites currently in orbit and which are partially dedicated to the science: CoRoT (COnvection ROtation and planetary Transits) of the CNES and ESA and Kepler of NASA.

Valérie Van Grootel has made asteroseismology her area of research. She models the physical mechanisms at work in a star type as highly evolved and rare as those that are known as extreme horizontal branch stars. Having depleted its hydrogen core, a star begins to burn its helium in the inner layers while its envelope dilates considerably. This phase, which our sun will reach in around five billion years, is translated on the surface by a change of colour to red.  However, the red giant thus formed will very rapidly cast off its envelope, thus losing an impressive amount of its mass. All that remains is the core that burns helium and which has a radius of only 15% of the sun. Theories about stellar evolution speak about the extreme horizontal branch.  These are evolved stars that are not very numerous and that are small in magnitude.