Presentation 1 : Oral
Search and characterization of extra-solar planets with HARPS
F. Bouchy
Since 1995 more than 70 exoplanets have been detected by radial
velocity survey. HARPS is a new spectrograph specially dedicated to
the search for extra-solar planets by high precision Doppler measurements. HARPS is presently in its integration phase and will
be installed on the ESO 3.6-m telescope at La Silla at the end of 2002. Thanks to its high luminosity and spectral resolution, its exceptional thermo-mechanical stability and vacuum operation, HARPS is expected to attain a precision close to the 1 m/s limit and to detect companions up to 5 earth mass. Fully adapted to characterize the masses (and then densities) of planet candidates detected by transits, one part of its
program will be dedicated to the radial velocity follow-up of transit events detected by COROT.
Presentation 2 : Oral
New results on ground-based asteroseismology of solar-like stars
F. Bouchy
Observing stellar oscillations provides a powerful probe for studying stellar interiors. The frequencies of these modes depend on the properties of the star, such as sound speed, density, and rotation. The five-minute oscillations in the Sun, induced by stochastic excitation of its convective zone, have provided a wealth of information about the solar interior and has led to significant revisions to solar models. Recently, thanks to high precision Doppler measurements, solar-like oscillations have been clearly detected in a growing list of main sequence and subgiant stars. New results and prospects in this field are presented.