FROM VERY LOW MASS STARS TO EXTRASOLAR PLANETS

Using the Phoenix atmosphere code, we have addressed the modelling of the spectral and evolutive properties of Very Low Mass Stars (VLMs), brown dwarfs, known Extrasolar Giant Planets (EGPs), and started on that of Extrasolar Telluric Planets (ETPs). In this paper, we review this situation and we summarize the spectral properties of EGPs. We establish the most favorable observation conditions (i.e. maximum luminosity contrast of the planet to the primary star). We also explore constraining cases such as HD209458b, OGLE-TR56b and other transits.