Kipfer, Kristina Anna (2025). A Journey through the Icy Solar System: Laboratory Studies on the Physical and Chemical Processes of Frozen Environments in Space. (Thesis). Universität Bern, Bern
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Abstract
Ice is ubiquitous in space: On the surface of dust grains in cold and dense molecular clouds, in protoplanetary disks, and in our own solar system. There, ice shapes the surface of a multitude of moons, comets, and minor bodies. Understanding the chemical and physical processes in the ices over their life-cycle is of utmost importance to understand the inheritance of matter through different evolutionary stages and the manner in which icy surfaces can be altered after formation. Over the course of this thesis, various processes occurring in solar system ices have been investigated using a newly built setup called ICEBEAR. First, the trapping of the hypervolatile molecules N2 and CO in the major cometary ices H2O and CO2 was quantified and the results applied to comet 67P/Churyumov-Gerasimenko. The hypervolatiles have been observed to co-desorb with both major ice constituents, highlighting that realistic ice mixtures have to be used in the laboratory to study the trapping mechanisms of volatile molecules in cometary ices. Second, the energetic processing of Kuiper belt ice analogues containing methane via electrons was investigated and the volatile irradiation products were studied. A number of hydrocarbons and presumed complex organic molecules could be formed in this way and the different ices and irradiation durations were compared to each other. It was determined that the addition of nitrogen to a H2O:CH4 ice led to less volatile irradiation products forming, which were suspected to be incorporated in a non-volatile residue. Finally, H2O:CH3OH:N2 ices were heavily energetically processed using electrons and the resulting residues were investigated using Raman spectroscopy. The Raman spectra showed similarities to the insoluble organic matter found in the most primitive solar system bodies. It was determined that the residues only yielded valuable Raman spectra if the ice was irradiated twice, with the second time in an ice-free environment. Different temperature combinations for the first and second irradiation were investigated, with a tentative dependence of the Raman parameters on the temperature being observed. In addition to the experiments conducted with the ICEBEAR laboratory setup, two other projects were completed. The detectability of polycyclic aromatic hydrocarbons with the space prototype laser desorption mass spectrometer ORIGIN was quantified, expanding the database of detectable molecules with the instrument. In a second project, data from the Atacama Large Millimeter/submillimeter Array was used to investigate the inventory of complex organic molecules in a protoplanetary disk. This project compared two regions of interest in the disk and column densities for a variety of organics were determined. This thesis expands the knowledge of processes occurring in solar system ices and further suggests that the processing of simple ices via electrons is a viable method to form the insolubleorganic matter found in primitive solar system bodies. The results help understand the formationand evolution of the solar system building blocks and how the processing of ices contributed to the molecular complexity observed.
| Item Type: | Thesis |
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| Dissertation Type: | Cumulative |
| Date of Defense: | 28 February 2025 |
| Subjects: | 500 Science > 520 Astronomy 500 Science > 530 Physics |
| Institute / Center: | 08 Faculty of Science > Physics Institute 10 Strategic Research Centers > Center for Space and Habitability (CSH) |
| Depositing User: | Hammer Igor |
| Date Deposited: | 05 Dec 2025 09:29 |
| Last Modified: | 05 Dec 2025 09:29 |
| URI: | https://boristheses.unibe.ch/id/eprint/6941 |
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