<> "The repository administrator has not yet configured an RDF license."^^ . <> . . "Probing the early Milky Way with stellar spectroscopy"^^ . "Stars preserve the fossil records of the kinematical and chemical evolution of individual building\r\nblocks of the Milky Way. In its efforts to excavate this information, the astronomical community\r\nhas recently seen the advent of massive astrometric and spectroscopic observing campaigns that are\r\ndedicated to gather extensive data for millions of stars. The exploration of these vast datasets is at the\r\nheart of the present thesis. First, I introduce ATHOS, a data-driven tool that employs spectral flux ratios\r\nfor the determination of the fundamental stellar parameters effective temperature, surface gravity, and\r\nmetallicity, upon which all higher-order parameters like detailed chemical abundances critically rely.\r\nATHOS’ robustness and widespread applicability is not only showcased in a comparison to large-scale\r\nspectroscopic surveys and their dedicated pipelines, but it is also demonstrated to be able to compete\r\nwith highly specialized parameterization methods that are tailored to high-quality data in the realm\r\nof studies with low target numbers. An in-depth study of the latter kind is outlined in the second\r\npart of this thesis, where I present a chemical abundance investigation of the metal-poor Galactic halo\r\nstar HD 20. Using spectra and photometric time series of utmost quality in combination with modern\r\nasteroseismic and spectroscopic analysis techniques, I deduce a comprehensive, highly accurate, and\r\nprecise chemical pattern that proves HD 20 worthy of being added to the short list of metal-poor\r\nbenchmark stars, both for nuclear astrophysics and in terms of stellar parameters. The decomposition\r\nof the chemical pattern shows an imprint from s-process nucleosynthesis on top of the already in itself\r\nrarely encountered enhancement of r-process elements. In the absence of a companion that could\r\nact as polluter, this poses a striking finding that points towards fast and efficient mixing in the early\r\ninterstellar medium prior to HD 20’s formation. In the third and last part, spectroscopic data from\r\nthe SDSS/SEGUE surveys are combined with astrometry from the Gaia mission to form a sample of\r\nseveral hundred thousand chemodynamically characterized halo stars that is scrutinized to establish\r\nlinks between globular clusters and the general halo field star population. Based on the identified\r\nsample of probable cluster escapees that includes both first-generation and second-generation (former)\r\ncluster stars, I provide important observational constraints on the overall cluster contribution to the\r\nbuildup of the Galactic halo. A highly interesting – yet tentative – finding is that for those populations\r\nof stars that were lost early on, the first-generation fraction appears higher compared to groups that are\r\ncurrently being stripped or still bound to clusters. This observation could indicate either a dominant\r\ncontribution from since dissolved low-mass clusters or that early cluster mass loss preferentially\r\naffected first-generation stars."^^ . "2020" . . . . . . . "Michael"^^ . "Hanke"^^ . "Michael Hanke"^^ . . . . . . "Probing the early Milky Way with stellar spectroscopy (PDF)"^^ . . . "Thesis_Hanke.pdf"^^ . . . "Probing the early Milky Way with stellar spectroscopy (Other)"^^ . . . . . . "indexcodes.txt"^^ . . . "Probing the early Milky Way with stellar spectroscopy (Other)"^^ . . . . . . "lightbox.jpg"^^ . . . "Probing the early Milky Way with stellar spectroscopy (Other)"^^ . . . . . . "preview.jpg"^^ . . . "Probing the early Milky Way with stellar spectroscopy (Other)"^^ . . . . . . "medium.jpg"^^ . . . "Probing the early Milky Way with stellar spectroscopy (Other)"^^ . . . . . . "small.jpg"^^ . . "HTML Summary of #28676 \n\nProbing the early Milky Way with stellar spectroscopy\n\n" . "text/html" . . . "520 Astronomie"@de . "520 Astronomy and allied sciences"@en . .