Enrichment of planetary surfaces by asteroid and comet impacts

Asteroids and comets have played a very important role in the early evolution of the Earth. Some theories suggest that significant amounts of water and organic material were delivered to Earth through asteroid and comet impacts. These events have affected not only our Earth but many other planetary surfaces within the Solar System. Moreover, the delivery mechanisms still operate nowadays. We have performed computer simulations to study the asteroidal and cometary contribution to the water and organic budget of Mercury and Mars. Interestingly, our own Solar System is not the only place that harbours asteroids and comets. About 20 stars are known to hold warm and cold debris disks, analogues of the Main Asteroid Belt and the Kuiper Belt. The role of these exo- asteroids and exo-comets in the delivery of water and organics to exoplanets is unknown. To shed light on these delivery processes we extrapolate our Solar System scenarios to the exoplanetary system HR 8799.