Introduction

• Konrad Schmidt (HZDR, Germany)

Room: online Monthly SNAQs – Introducing a new, virtual school format discussing questions related to nuclear astrophysics

Presenting the NPA-X school

• Rosanna Depalo (Università degli Studi di Milano and INFN Milano, Italy)

Room: online

Determining the compositions of stars using 3D non-LTE models

• Anish Amarsi (Uppsala University, Sweden)

Room: online First lecture The compositions of stars are usually determined by comparing observations of stellar spectra against theoretical models. The accuracy of the inferred compositions is often limited by the accuracy of the models. For stars of similar mass to the Sun, arguably the most accurate models available today are based on three-dimensional radiation-hydrodynamics simulations ("3D"), together with radiative transfer methods that take into account the non-local coupling between light and matter (non-local thermodynamic equilibrium, or "non-LTE"). I shall talk about these 3D non-LTE models and their application to the Sun and other stars in the Milky Way.

Moderated questions

• Arūnas Kučinskas (Vilnius University, Lithuania)

Room: online

First Stars - the importance of accurate stellar abundances

• Ása Skuladottir (University of Florence, Italy)

Room: online Second lecture The properties of the first stars in the Universe remain elusive. The impact of the first stellar generation was significant, as they provided the first ionising radiation, metals and dust in the Universe, but their study is very challenging. No metal-free star has been observed to date, but we can study them through their chemical imprint left in the second generation of stars. Thus, to correctly interpret the available data, and gain a comprehensive understanding of the first stars, accurate stellar abundances are of utmost importance.

Moderated questions

• Andreas Korn (Uppsala University, Sweden)

Room: online

Abundances of Sr and Zr in the atmospheres of red giants in Galactic globular cluster 47 Tuc

• Edgaras Kolomiecas (Vilnius University, Lithuania)

Room: online It was a long‐standing assumption that Galactic globular clusters (GGCs) are homogeneous objects consisting of stars that have the same age and chemical composition. However, research done during the last several decades has unexpectedly revealed that almost all GGCs harbour multiple stellar populations (MPs) consisting of stars that differ in: their abundances of light chemical elements (e.g., O, Na, Al); distributions within the cluster; and kinematical properties. By combining abundances of neutron capture and light chemical elements and determining their abundance ratios it is feasible to constrain the possible evolutionary scenarios of GGCs. To identify the possible polluter stars and the possible pollution scenarios we determined abundances of Sr and Zr, both light s‐process chemical elements, and Na in the atmospheres of RGB stars in GGC 47 Tuc. We use the obtained results to discuss the accuracy needed for the abundance determinations to detect the existence of possible correlations/anticorrelations between the abundances of chemical elements in the GGCs, as well as possible connections between the chemical composition of these stars and their kinematical properties and implications for constraining the possible evolutionary scenarios of the GGCs.

Moderated questions

• Camilla J. Hansen (Goethe University, Frankfurt, Germany)

Room: online

Round-table discussion Room: online Questions that were compiled in the chat during and after lectures and breakout session will be answered and discussed.