Extrasolar Planetary Systems

Abstract.

Radial Velocity surveys have revealed up to now about 100 extra-solar planets (M sin i < 10 M _Jup ) and 7 multi-planetary systems. The discovered planets present a wide variety of orbital elements and masses, which are raising many problems and questions regarding the processes involved in their formation. But the analysis of the distributions of orbital elements, like the period and eccentricity distributions is already giving some constraints on the formation of the planetary systems. Furthermore, the study of the planet host stars has revealed the impressive role of the stellar metallicity on the giant planet formation. The chemical composition of the molecular cloud is probably the key parameter to form giant planets. In this article we will review the current status of the research on this subject.