Sema Caliskan (Uppsala University): Non-LTE modelling of neutron-capture elements: from atomic structure to stellar abundances (Pre-defence seminar)

Thursday 6 Nov 2025, 14:00 → 15:00 Europe/Stockholm

90101Å

Title: Non-LTE modelling of neutron-capture elements: from atomic structure to stellar abundances
Speaker: Sema Caliskan
Affiliation: Uppsala University
Time: Thursday 6 November 2025, 14:00 to 15:00
Location: 90101Å

Abstract: The cosmic origin of elements heavier than iron remains one of the open questions in astrophysics. These elements are produced through neutron-capture processes in diverse astrophysical sites, but to disentangle their contributions and galactic evolution, we rely on accurate stellar abundances. Deriving these abundances requires reliable non-LTE models of stellar spectra. However, for many heavy elements, non-LTE modelling is still missing due to the scarcity of accurate atomic data.

During my PhD, I have worked at this intersection, aiming to improve atomic data and construct more accurate non-LTE models for heavy elements. I will present results from different stages of this work: from atomic structure to non-LTE modelling of copper and silver. I will show how improved atomic data, such as hydrogen collision rates, impact non-LTE abundance determinations of these elements, and how refined abundance trends in turn sharpen our understanding of nucleosynthetic origins and galactic chemical evolution.