Kuipers, Stefan (2021) Thorium, europium and s-process elements in Galactic halo vs. Gaia-Enceladus. Master's Thesis / Essay, Physics.
|
Text
mPHYS_2021_KuipersS.pdf Download (2MB) | Preview |
|
![[img]](https://fse.studenttheses.ub.rug.nl/style/images/fileicons/text.png) |
Text
Toestemming.pdf Restricted to Registered users only Download (117kB) |
Abstract
In this thesis I have measured the abundances of a range of chemical elements, including heavy r-process elements europium and thorium in a group of 6 stars in the Milky Way, selected from the sample of Nissen & Schuster 2010. My sample includes 4 halo stars, of which 2 are likely to be from the dwarf galaxy Gaia Enceladus that merged with the Milky Way around 10 Gyr ago, and also includes 2 stars which are likely from the thick disk of the Milky Way. This is the first time that Th has been detected in any of these stars. The analysis was carried out on high spectral resolution, high signal-to-noise VLT/UVES spectra, using spectral synthesis, and the spectral parameters determined by Nissen & Schuster. There are differences between my results and those of Nissen & Schuster but the general characteristics of the sample remain the same and are consistent with the results presented by Nissen & Schuster. I have found that Gaia-Enceladus stars have lower [Mg/Fe] than either the other 2 halo stars or the thick disk stars, in agreement with Nissen & Schuster. In addition I show that [Eu/Mg] is higher in Gaia-Enceladus stars, which indicates enhanced r-process enrichment. However [Th/Fe] and the other elements I have measured are remarkably similar for all the 6 stars. This shows that the differences in chemical properties of my sample of stars with 3 different origins are subtle.
| Item Type: | Thesis (Master's Thesis / Essay) |
|---|---|
| Supervisor name: | Tolstoy, E. and Even, J. |
| Degree programme: | Physics |
| Thesis type: | Master's Thesis / Essay |
| Language: | English |
| Date Deposited: | 03 Aug 2021 14:33 |
| Last Modified: | 03 Aug 2021 14:33 |
| URI: | https://fse.studenttheses.ub.rug.nl/id/eprint/25578 |
Actions (login required)
 |
View Item |