Abstract

Stars are born with gas-rich protoplanetary discs that typically survive for a few million years before dispersing, after which they are left with the planetary bodies that formed within their protoplanetary systems. In our Solar System, this process resulted in a diverse string of terrestrial planets, gas- and ice-giants, and two belts of `planetesimals’ (the Asteroid Belt and the Edgeworth-Kuiper Belt). Recent surveys in our Galaxy have revolutionized our understanding of the abundance of such planetary system components elsewhere with the detection of 1000s of main sequence planets, 100s of `debris discs’ (massive analogs of the Asteroid and Kuiper belts) and even greater numbers of protoplanetary discs around pre-main sequence stars where planets and planetesimals are either still forming, or yet to do so. Although the formation of planets and planetesimals is now understood to be the rule rather than the exception, many of the discs and planets observed appear unlike those in our Solar System: the details connecting young protoplanetary discs to the main sequence planetary systems in which life may emerge remain unclear. In this talk, I will explore the origins and diversity of planetary systems, and connect these to the most recent research and observations of planetesimal belts and debris discs.