Related papers: Evolution of surface CNO abundances in massive sta…
Tentative evidence that the properties of evolved stars with planets may be different from what we know for MS hosts has been recently reported. We aim to test whether evolved stars with planets show any chemical peculiarity that could be…
We study the evolution of nitrogen in the Galactic halo, thick disc, thin disc and bulge by comparing detailed chemical evolution models with recent observations. The models used in this work have already been constrained to explain the…
We carefully analyze how the abundance of Nitrogen over Oxygen evolves when dependent on metallicity stellar yields with a primary component of N proceeding from AGBs stars are used. We show the results obtained with a chemical evolution…
The evolution of C and O abundances in the Milky Way can impose strong constraints on stellar nucleosynthesis and help understanding the formation and evolution of our Galaxy. The aim is to review the measured C and O abundances in the disk…
Accurate atmospheric parameters and chemical composition of planet-hosting stars are crucial for characterising exoplanets and understanding their formation and evolution. Our objective is to uniformly determine the atmospheric parameters…
We investigate the chemical evolution of N/O using a sample of 45 local star-forming galaxies (SFGs) from the CLASSY survey. This sample spans a wide range of galaxy properties, with robust determinations of nitrogen and oxygen abundances…
In some recent works, the C/O abundance ratio in high-metallicity stars with planets is found to vary from 0.4 to about 1.0. This has led to discussions about the existence of terrestrial planets with a carbon-dominated composition that is…
Carbon and oxygen abundances in F and G main-sequence stars ranging in metallicity from [Fe/H] = -1.6 to +0.5 are determined from a non-LTE analysis of CI and OI atomic lines in high-resolution spectra. Both C and O are good tracers of…
We study the relation between nitrogen and oxygen abundances as a function of metallicity for a sample of emission-line objects for which a direct measurement of the metallicity has been possible. This sample is representative of the very…
The success of galactic archaeology and the reconstruction of the formation history of our galaxy critically relies on precise ages for large populations of stars. For evolved stars in the red clump and red giant branch, the carbon to…
The material in planet-forming disks determines the composition of planets; hence, it is crucial to understand the physical and chemical processes that set the abundance and distribution of key volatiles. James Webb Space Telescope…
We study the evolution of nitrogen resulting from a set of spiral and irregular galaxy models computed for a large number of input mass radial distributions and with various star formation efficiencies. We show that our models produce a…
We investigate the surface nitrogen content of the six magnetic O stars known to date as well as of the early B-type star tau Sco. We compare these abundances to predictions of evolutionary models to isolate the effects of magnetic field on…
The VLT-Flames Survey for Massive Stars (Evans05,Evans06) provides recise measurements of rotational velocities and nitrogen surface abundances of massive stars in the Magellanic Clouds. Specifically, for the first time, such abundances…
It is shown that, in the case of early B-type main-sequence stars, of the three ratios N/C, C/O, and N/O which are regarded as indicators of stellar evolution, the ratio N/O is more reliable since it seems to be insensitive to…
Massive stars burn hydrogen through the CNO cycle during most of their evolution. When mixing is efficient, or when mass transfer in binary systems happens, chemically processed material is observed at the surface of O and B stars. ON stars…
The composition of giant planets is imprinted by their migration history and the compositional structure of their hosting disks. Studies in recent literature investigate how the abundances of C and O can constrain the formation pathways of…
We present measurements of the gas-phase C/O abundance ratio in six H II regions in the spiral galaxies M101 and NGC 2403, based on ultraviolet spectroscopy using the Faint Object Spectrograph on the Hubble Space Telescope. The C/O ratios…
Massive stars rotate faster, on average, than lower mass stars. Stellar rotation triggers hydrodynamical instabilities which transport angular momentum and chemical species from the core to the surface. Models of high-mass stars that…
Our main aim is to determine carbon-to-nitrogen and carbon isotope ratios for evolved giants in the open clusters NGC 2324, NGC 2477, and NGC 3960, which have turn-off masses of about 2 Msun, and to compare them with predictions of…