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Review - there and back again: the making and destruction of dusty planetesimals

Wurm, G (Münster)
Tuesday 18 August 2009, 09:00-09:40

Meeting Room 2, CMS


A dust particle has to take a number of different roads to be incorporated into a planet. On the constructive side, collisions gentle enough might stick the particle to other particles and lead to growth of larger objects. Ultimately, beyond any detail, this is how planetesimals, km-size precursors to planets and terrestrial planets further on form. Collisions are therefore among the most fundamental processes in planet formation. In detail they have their share in shaping the size distribution and morphology of evolving bodies and to set formation time scales of larger objects in protoplanetary disks. Sticking, rebound, fragmentation, and reaccretion (the latter especially by gas drag) are important results of individual collisions. How far we can get along the size scale of growth from dust upward and which collisions / conditions would be needed to get to planetesimals will be covered in this talk. As the evolving bodies are not isolated in their collisions but embedded in a gaseous protoplanetary disk, other processes can support, prevent, or even undo the growth of large bodies. Eventually, these processes might be of similar importance as the collisional growth and put some dependence of the formation processes to the radial distance from the star within the disk. Planetesimal and planet formation does not necessarily proceed the same way all over the disk. I will suggest some thoughts on this.

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