Stars and planets at high spatial and spectral resolution

Abstract

The work presented in this thesis involves the development of new instrumental techniques and analysing tools, combining high spectral resolution with high spatial information, with the aim to increase our understanding of the formation and evolution of stars and planets. First, a novel instrumental concept is presented that aims to achieve high spatial and spectral resolution by combining existing Echelle spectrographs with existing optical interferometers. Subsequently, several studies combining high spatial and spectral resolution are presented. We investigate the immediate environment of the massive young stellar object MWC349A, using the VLT-interferometer. New methods are presented to analyse the Rossiter-McLaughlin effect during stellar eclipses. By using this effect it is possible to obtain spatial information on stellar surface scales, something difficult to achieve by other means. Using these new tools we show that the spin axes in both stars of in the DI Herculis system are strongly tilted with respect to the orbital angular momentum. This solves a 20-year-old riddle about the DI Herculis system, involving its apparently slow apsidal motion. In the final chapter of this thesis sodium measurements for the atmosphere of the extrasolar planet HD209458b using ground-based transmission spectroscopy are presented.