X-shooter Observations of Carbon Enhanced Metal-Poor Stars in Sculptor

Sardjan, Danny (2020) X-shooter Observations of Carbon Enhanced Metal-Poor Stars in Sculptor. Master's Thesis / Essay, Astronomy.

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Abstract

The true fraction of Carbon Enhanced Metal-Poor (CEMP) stars in dwarf spheroidal galaxies is poorly known. It is currently thought that there are unusually few, es- pecially in the case of CEMP-no stars, compared to the halo of the Milky Way. CEMP-no stars are believed to have been enriched by the first zero-metallicity massive stars because they are so common among the most metal-poor stars. The more common CEMP-s stars differ from CEMP-no stars in an enhancement in Ba. It is possible that the lack of CEMP stars in dwarf spheroidal galaxies is because past spectroscopic studies of individual stars in these galaxies have tended to ignore C-rich stars as they are hard to analyse, especially with limited wavelength range spectra, due to the presence of broad, strong Carbon features over the entire spec- trum. This project uses the long wavelength range of X-shooter to study three stars that have been previously identified as C-rich in the Sculptor dwarf spheroidal. We use the MARCS stellar atmosphere models in combination with TURBOSPEC to generate synthetic spectra. We compare these synthetic spectra to the observations to determine the abundance of chemical elements that have identified absorption lines in the spectrum. For the first time we have successfully measured the abun- dances of C, N, Fe, Y, Ba, La, Nd and determined an upper limit of Eu in these stars.

Item Type:	Thesis (Master's Thesis / Essay)
Supervisor name:	Tolstoy, E.
Degree programme:	Astronomy
Thesis type:	Master's Thesis / Essay
Language:	English
Date Deposited:	04 Jun 2020 11:19
Last Modified:	04 Jun 2020 11:19
URI:	https://fse.studenttheses.ub.rug.nl/id/eprint/22009

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