TOPoS: IV. Chemical abundances from high-resolution observations of seven EMP stars

Understand

Extremely metal-poor stars provide us with indirect information on the first generations of massive stars.

• The TOPoS survey has been designed to increase the census of these stars and to provide a chemical inventory that is as detailed as possible.
• Seven of the most iron-poor stars have been observed with the UVES spectrograph at the ESO VLT Kueyen 8.2m telescope to refine their chemical composition.
• We analysed the spectra based on 1D LTE model atmospheres, but also used 3D hydrodynamical simulations of stellar atmospheres.