| dc.contributor.advisor | Böhnhardt, Hermann Dr. | |
| dc.contributor.author | Ruzicka, Birko-Katarina | |
| dc.date.accessioned | 2019-11-19T11:43:53Z | |
| dc.date.available | 2019-11-19T11:43:53Z | |
| dc.date.issued | 2019-11-19 | |
| dc.identifier.uri | http://hdl.handle.net/21.11130/00-1735-0000-0005-12AF-2 | |
| dc.identifier.uri | http://dx.doi.org/10.53846/goediss-7727 | |
| dc.language.iso | eng | de |
| dc.rights.uri | http://creativecommons.org/licenses/by-nc-nd/4.0/ | |
| dc.subject.ddc | 910 | de |
| dc.subject.ddc | 550 | de |
| dc.title | Layerings in the nucleus of comet 67P/Churyumov-Gerasimenko | de |
| dc.type | doctoralThesis | de |
| dc.contributor.referee | Pack, Andreas Prof. Dr. | |
| dc.date.examination | 2019-11-04 | |
| dc.description.abstracteng | The Rosetta mission to delivered images of comet 67P’s nucleus at unprecedented
resolution which indicate the presence of a global layering system. By
merging techniques of structural geology, statistical image processing, and solar
system science, this thesis aims to contribute to the understanding of the
formation of the layerings, and consequently the formation of cometary nuclei
as a whole.
I describe the two distinctive approaches I used to study the layerings’ orientation
on both lobes of comet 67P’s nucleus. First, I mapped layering-related
linear features on a 3D shape model of the nucleus, onto which I projected
high-res OSIRIS images. I selected only lineaments of substantial curvature,
and used a plane-fitting algorithm to find the normals to the layering planes
represented by these lineaments. I used the normals to confirm previous authors’
results, including that the layering systems on the comet’s two lobes are
geometrically independent from each other. My results rule out the proposal
that 67P’s lobes represent collisional fragments of a much larger, layered body.
Second, I developed a Fourier-based image analysis algorithm to detect lineament
structures at pixel-precision. I analysed the layering-related, sub-parallel
linear features exposed on the Hathor cliff on the comet’s Small Lobe. I found
my algorithm to be a broadly applicable, powerful tool for automating the detection
of layerings in images where conventional edge-detection algorithms
are not effective. When correctly configured to the target conditions, I found
the algorithm to have a higher signal-to-noise detection sensitivity than a human,
while also reducing over-interpretation due to bias.
In summary, I studied the layerings in the nucleus of comet 67P using several
unconventional approaches and constrained their lateral extent, curvature,
and to a degree also their thickness. Ultimately, I nominated two mechanisms
that could have formed these layerings in cometary nuclei. | de |
| dc.contributor.coReferee | Böhnhardt, Hermann Dr. | |
| dc.contributor.thirdReferee | Christensen, Ulrich Prof. Dr. | |
| dc.contributor.thirdReferee | Schröter, Matthias Dr. | |
| dc.contributor.thirdReferee | Penasa, Luca Dr. | |
| dc.contributor.thirdReferee | Kley, Jonas Prof. Dr. | |
| dc.subject.eng | layerings | de |
| dc.subject.eng | cometary nuclei | de |
| dc.subject.eng | comet 67P/Churyumov-Gerasimenko | de |
| dc.subject.eng | structural analysis | de |
| dc.subject.eng | image processing | de |
| dc.identifier.urn | urn:nbn:de:gbv:7-21.11130/00-1735-0000-0005-12AF-2-0 | |
| dc.affiliation.institute | Fakultät für Geowissenschaften und Geographie | de |
| dc.subject.gokfull | Geologische Wissenschaften (PPN62504584X) | de |
| dc.identifier.ppn | 168218451X | |