Advanced Characterization of Exoplanet Host Stars

Abstract: The spectroscopic determination of stellar properties is important for subsequent studies of exoplanet atmospheres. In this thesis, HARPS data for 6 exoplanet-hosting, late-type stars is processed to achieve an average signal-to-noise ratio of ~105. Together with line data, the SME tool is used to synthesize spectra and interpolate model photospheres with which chi-square minimization is performed. Fundamental parameters are derived to an overall precision of 191 K in effective temperature, 0.88 dex in surface gravity and 0.21 dex in metallicity. For 5 of the stars, the parameters are thereafter used to compute specific intensities across the stellar discs. Primary improvements could be made in regards to the stellar models, i.a. through the update of atomic properties and inclusion of magnetic fields. The numerical derivation can also be handled more carefully by excluding parameter-insensitive spectral regions.