After hydrogen and helium, oxygen, carbon, and nitrogen—hereinafter, the CNO elements—
are the most abundant species in the universe. They are observed in all kinds of …

Recent observations of GN-z11 with JWST/NIRSpec revealed numerous oxygen, carbon,
nitrogen, and helium emission lines at z= 10.6. Using the measured line fluxes, we derive …

Context. Grids of stellar evolution models with rotation using the Geneva stellar evolution
code (GENEC) have been published for a wide range of metallicities. Aims. We introduce …

We study a sample of single Galactic post-asymptotic giant branch (post-AGB) stars with
known surface chemical composition. Gaia EDR3 and Gaia DR3 parallaxes have enabled …

Well-studied very metal-poor (VMP,[Fe/H]<− 2) stars in the inner Galaxy are few in number,
and they are of special interest because they are expected to be among the oldest stars in …

Context. Nitrogen isotopic ratios are a key tool for tracing Galactic stellar nucleosynthesis.
Aims. We present the first study of the 14 N/15 N abundance ratio in the outer regions of the …

Context. The study of post-asymptotic giant branch (post-AGB) stars is a valuable tool in
improving our understanding of poorly known aspects of the evolution of the stars …

Context. Stellar models and nucleosynthetic yields of primordial to extremely metal-poor
(EMP) stars are crucial to interpret the surface abundances of the most metal-poor stars …

We discuss the evolution of stars through the asymptotic giant branch, focusing on the
physical mechanisms potentially able to alter the surface chemical composition and on how …

ABSTRACT Atacama Large Millimeter/submillimeter Array (ALMA) observations revealed
the presence of significant amounts of dust in the first Gyr of Cosmic time. However, the …