The physical properties of extra-solar planets

Tremendous progress in the science of extrasolar planets has been achieved the discovery of a Jupiter orbiting the nearby Sun-like star 51 Pegasi in1995. Theoretical models have now reached enough maturity to predict the properties of these new worlds, mass, radius, atmospheric, and can be confronted with available observations. We review our knowledge of the physical properties of exoplanets, internal structure composition, atmospheric signatures, including expected biosignatures for-Earth planets, evolution, and the impact of tidal interaction and stellar on these properties for the short-period planets. We discuss the recent theoretical achievements in the field and the still pending. We critically analyse the different solutions suggested to explain large radii of a significant fraction of transiting exoplanets. attention is devoted to the recently discovered transiting objects in overlapping mass range between massive planets and low-mass brown dwarfs, the ambiguous nature of these bodies, and we discuss the possible diagnostics to identify these two distinct populations. We also our present understanding of planet formation and critically examine the suggested formation mechanisms. We expect the present review to the basic theoretical background to capture the essential of the of exoplanet formation, structure and evolution, and the related signatures.