Anders Johansen
Professor
Dynamics and Erosion of Solids in Protoplanetary Disks
Author
Summary, in English
outer disk are incorporated in the initial clump. Once the critical density is reached, the clumps gravitationally collapse into planetesimals. Then, through the accretion of pebbles, other planetesimals and gas, planets form.
In this thesis I cover the early stages of the planet formation process. Based on results of protoplanetary disk observations and laboratory experiments, I investigate the efficiency of the streaming instability given multiple solid sizes and their interaction with the gas. In Paper I and Paper III, we found that the multi-species streaming instability changes the dynamics of the system. We found that particles with different sizes interact with each other through the gas. The large species, which are located close to the midplane, trigger the streaming instability and drive the vertical and radial diffusion of all species. In both Papers I and III we found that there is no clear trend in how the steepness of the particle size distribution in combination with the minimum and maximum particle size affects the outcome of the instability. In Paper III we furthermore conclude that the multi-species instability is successful in forming particle clumps and that numerical effects such as particle number do not lead to significant change in the efficiency of clump formation.
In this thesis I also investigate the how gas erosion affects disk solids. In Paper II, we found that solids in the inner disk
on eccentric orbits erode fast, due to the headwind from the gas. We also found that along the surface of the solid,
erosion is fastest near the top and bottom and slowest near the stagnation points of the flow.
Department/s
- Lund Observatory - Undergoing reorganization
Publishing year
2021-03-15
Language
English
Document type
Dissertation
Publisher
Department of Astronomy and Theoretical Physics, Lund University
Topic
- Astronomy, Astrophysics and Cosmology
Keywords
- Fysicumarkivet A:2021:Schaffer
Status
Published
Supervisor
- Anders Johansen
- Michiel Lambrechts
- Chao-Chin Yang
ISBN/ISSN/Other
- ISBN: 978-91-7895-790-3
- ISBN: 978-91-7895-789-7
Defence date
29 April 2021
Defence time
15:00
Defence place
Lundmarksalen Astronomihuset Sölvegatan 27 ] Join via zoom: https://lu-se.zoom.us/j/61604689514?pwd=UFFPMWVxTnVHMDdxTm5DRzMvYjVQdz09 passcode 2020
Opponent
- Jacob Simon (Assistant professor)