Project P9: Photospheric and chromospheric models of debris disk host stars (Hamburg Observatory)


Recent studies of debris disk host stars have shown that these stars are often fast rotators, some of them harbor magnetic fields and – again some of them – show rather unexpected evidence for chromospheric and even coronal activity. As a consequence new effects must be included in any state-of-the-art modeling of these stars. The main task of this project is to improve the modeling of the atmospheres of debris disk central stars and provide synthetic spectra for these objects; at the same time the relevant stellar parameters and elemental abundances will be provided. We also plan to investigate the influence of the chromospheric and possibly coronal corrections to the far-IR spectra as well as effects of fast stellar rotation on the stellar parameters that were recently realized to be important for debris disks and study possible activity diagnostics for these objects. The results will be important as inputs for the debris disk simulations, and the far IR spectra will be useful to disentangle the stellar and disk contributions to the observed spectra (projects P1–P4). We will also provide information on stellar UV fields for the project P8.