|Description:|| With the detection of hundreds of extrasolar planets over the past years and, thus, with the discovery that planetary systems can be quite different to our solar system, planet-formation studies have become a focus of modern astrophysical research. I will review the different stages of planet formation, i.e. dust agglomeration, formation of planetesimals, accretion of terrestrial planets, gas accretion, and planetary migration, and will show recent results from experimental and theoretical investigations to clarify relevant physical processes and timescales.|
The image above shows the sequence of a collision between two high-porosity dust aggregates in the laborytory. Above a collision velocity of ~1 m/s collisions predominantly result in fragmentation, which makes the formation of planetesimals by direct hit-and-stick collisions unlikely.