Atomic processes in stellar atmospheres: towards high-accuracy stellar abundances for galactic archeology
The Swedish Research Council reached a decision on February 23, 2017 on project grants and starting grants on Natural and Engineering Sciences. The Department of Physics and Astronomy is granted 45.9 million SEK for the period 2016-2020 for in total six project grants and six starting grants. The projects will begin during 2017.
Paul Barklem, Astronomy and Space Physics, was granted 3.2 million SEK for the project “Atomic processes in stellar atmospheres: towards high-accuracy stellar abundances for galactic archeology” from the Swedish Research Council for the period 2016-2020.
The measurement of stellar chemical abundances is a fundamental problem in astrophysics. While spectral lines are routinely measured at accuracies of 1%, systematic errors dominate interpretation and errors in abundances are at least an order of magnitude larger. It can be reasonably expected, and evidence supports, that nature has more information to reveal if more accurate abundances are obtained. This project particularly examines the role of atomic processes involving hydrogen atoms, the simplest and most common element in the universe, on the stellar spectral lines of elements of interest and thus on the chemical abundance measured. This project will provide quantum mechanical calculations for inelastic collisions processes on many atoms of astrophysical importance using a novel method developed recently, thus solving a problem that has plagued a generation of stellar spectroscopists, and providing a significant legacy to stellar spectroscopy. With the advent of grids of 3D and non-LTE models, these advances will lead to improved accuracy in the measurement of stellar abundances. When coupled with the accurate stellar astrometry from Gaia and forthcoming large spectroscopic surveys such as 4MOST, this will open a new era of high-precision galactic archaeology and inform our understanding of how the Milky Way and galaxies in general form. Accurate modelling of stellar spectra will also impact other fields, such as the study of exoplanets and stellar physics in general.