My current fields of interest are in planetary and stellar physics. My main research activities are devoted to the study of giant and terrestrial solar and extra-solar planets, of substellar objects (brown dwarfs) and of a wide variety of stars (from low mass to very massive stars). The aim is to understand and to model the physical processes characteristic of (i) the formation, (ii) the atmospheric and interior structure and (iii) the evolution of substellar (planets, brown dwarfs) and stellar objects. I was awarded several prizes and distinctions: Royal Society Wolfson Research Merit Award in 2010 Gauss-Professorship from Goettingen Academy of Sciences in 2005 Johann WEMPE prize of the Astrophysikalisches Institut Potsdam in 2004 Bronze medal from the Centre National de la Recherche Scientifique (France) 1999