Exoplanetary systems: what have we learned so far?

 Until about 1995, the only planetary system that we knew of was our own solar system. Since then, several thousand planets orbiting stars other than the sun (exoplanets) have been discovered. The current count of confirmed exoplanets is set to cross 4000. It is now possible to carry out detailed and statistically meaningful demographic studies of exoplanets. Results from such studies are beginning to challenge our traditional ideas about planetary systems and their formation mechanisms that has been historically shaped by the observed properties of our solar system. In this talk, I will briefly summarise what we have learned so far about exoplanetary systems and the implications of these results for our understanding of the formation and subsequent evolution of planetary systems.