Model Atmospheres and Abundance Analyses of Main Sequence Stars
Ulrike Heiter (CWRU)
An important prerequisite for analysing the radiation emitted by the
photospheres of stars is an assumption on the structure of these
photospheres, i.e. a model of the change of thermodynamic quantities
with depth. A summary of the methods employed in the ATLAS9 code
(R. Kurucz) for calculating such model atmospheres, in particular
concerning the convective energy transport, will be given. The
calculation of large grids of model atmospheres enabled to quantify
the effect of different convection treatments on model structure and
observable quantities. The model atmospheres have also been used as
outer boundary conditions for stellar interior models. The main steps
involved in the determination of characteristic parameters and the
chemical composition of stellar atmospheres ("abundance analysis")
will be summarized. Results for a group of metal poor, population I,
A-F type dwarfs, the lambda Bootis stars, and their significance for
theories explaining the properties of this group will be given. As
another application of abundance analysis, a project on high
resolution spectroscopy of stars in the solar neighborhood will be
outlined. Finally, the status of the metallicity distribution
determined for dwarf stars accompanied by extrasolar giant planets
will be reviewed and complemented by current results.
