Wallenberg Academy Fellow Project

Planets form in discs of gas and dust orbiting young stars as dust and ice particles grow to ever larger bodies. An important stage in the planet formation process is the formation of km- scale planetesimals. Planetesimals are the building blocks of both terrestrial planets like the Earth and of the solid cores of gas giants like Jupiter. However, not all planetesimals become incorporated into planets. The asteroid belt between Mars and Jupiter and the Kuiper belt beyond Neptune are examples of planetesimal belts left over from the planet formation process. Frozen in time since the epoch of planet formation, the Kuiper belt objects provide a unique testbed for studying the prevailing conditions during planet formation.
The fundamental aim of this research project is to make computer simulations to find the sizes of planetesimals when they are born and compare to the observed size distribution in the Kuiper belt. This will give me insight into the dominant physical processes that determine the sizes of planetesimals and hence give constraints on how efficiently planetesimals grow to form planets. The second aim of the project is to gain understanding of the formation of binaries in the Kuiper belt. Binary planetesimals are unique to the Kuiper belt and their existence is key to understanding the conditions under which planetary systems form.
Short-period comets originate in the Kuiper belt. Comet cores are observed to contain a rich variety of organic molecules. Organic molecules are present in star-forming regions, but are too volatile to condense out at the Earth’s distance from the Sun. The building blocks of life may have been brought to Earth via comets. However, comet cores are typically 1-10 km in size, much smaller than the largest Kuiper belt objects. The third aim of the project is to model how small comet cores can form alongside large Kuiper belt objects.