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Room: Å10132 Häggsalen
Time: 13:15-15:00 [coffee break ~1400]
Title: Challenges in observational studies of heavy elements
Speaker: Camilla Juul Hansen
Affiliation: Goethe University Frankfurt
Heavy elements make up the largest part of the periodic table and they still pose a large number of open questions associated with their formation. Most of the heavy elements form via neutron captures that happen on a slow (s-process), intermediate (i-process) or a rapid (r-process) scale (when comparing to the following beta decays). In this talk I will present a homogeneous follow-up observational study targeting light as well as heavy elements in about 50 metal-poor stars. Our study provides new insights into the formation of the third r-process peak (Ir, Os, Pt) as well as challenges we face when deriving abundances of even heavier elements (Th), such as
shortcomings in our models as well as atomic physics. A few peculiar stars stand out in the study by either having a very high or very low level of heavy elements in their atmospheres. I will discuss the possible origin (spatial as well as nuclear formation) of these peculiar stars.
Title: Present-day abundances from OB stars
Speaker: Norbert Przybilla
Affiliation: University of Innsbruck
Short-lived massive OB-type stars are ideal indicators for present-day elemental abundances in star-forming regions in the solar neighbourhood, throughout wide parts of the Milky Way, and even in nearby galaxies. They complement other classical indicators like emission line spectra of HII regions while providing abundance data of high accuracy and precision. An overview is given on the progress made in the derivation of abundances for a wide range of chemical species. Results for OB-star populations in the Milky Way will be discussed, which provide observational present-day boundary values for the study of Galactochemical evolution, and for massive star evolution.