Related papers: S-Process Nucleosynthesis in Chemically Peculiar B…
We investigate the enrichment in elements produced by the slow neutron-capture process ($s$-process) in the globular clusters M4 (NGC 6121) and M22 (NGC 6656). Stars in M4 have homogeneous abundances of Fe and neutron-capture elements, but…
Presolar grains are microscopic dust grains that formed in the stellar winds or explosions of ancient stars that died before the formation of the solar system. The majority (~90% in number) of presolar silicon carbide (SiC) grains,…
The chemical content of the planetary nebula NGC 3918 is investigated through deep, high-resolution (R~40000) UVES at VLT spectrophotometric data. We identify and measure more than 750 emission lines, making ours one of the deepest spectra…
Half or more of stars more massive than our Sun are orbited by a companion star in a binary system. Many binaries have short enough orbits that the evolution of both stars is greatly altered by an exchange of mass and angular momentum…
Stellar photospheres of post-asymptotic giant branch stars bear witness to the internal chemical enrichment processes, integrated over their entire stellar evolution. Here we study post-AGB stars in the Large Magellanic Cloud (LMC). With…
Abundance observations indicate the presence of often surprisingly large amounts of neutron capture (i.e., s- and r-process) elements in old Galactic halo and globular cluster stars. These observations provide insight into the nature of the…
We analyze the chemical composition of the planetary nebula (PN) NGC 5315, through high-resolution (R = 40000) optical spectroscopy with UVES at the Very Large Telescope, and medium-resolution (R = 4800) near-infrared spectroscopy with FIRE…
S-type stars are late-type giants enhanced with s-process elements originating either from nucleosynthesis during the Asymptotic Giant Branch (AGB) or from a pollution by a binary companion. The former are called intrinsic S stars, and the…
We present nucleosynthesis predictions for massive (5-7 solar masses) asymptotic giant branch (AGB) stars of solar metallicity where we delay the onset of the superwind to pulsation periods of P =700-800 days. We found that delaying the…
Abundances of heavier elements (barium and beyond) in many neutron-capture-element-rich halo stars accurately replicate the solar system r-process pattern. However, abundances of lighter neutron-capture elements in these stars are not…
Measuring the merger rate density history of binary neutron stars (BNS) can greatly aid in understanding the history of heavy element formation in the Universe. Currently, second-generation Gravitational Wave (GW) detectors can only measure…
The origin of the heavy elements in the Universe is not fully determined. Neutron star-black hole (NSBH) and {binary neutron star} (BNS) mergers may both produce heavy elements via rapid neutron-capture (r-process). We use the recent…
Ground- and space-based observations of stellar heavy element abundances are providing a clearer picture of the chemical evolution of the Galaxy. A large number of (r)apid and (s)low neutron capture process elements, including the first…
Asymptotic giant branch (AGB) stars play a significant role in our understanding of the origin of the elements. They contribute to the abundances of C, N, and approximately $50\%$ of the abundances of the elements heavier than iron. An…
The recent parameterisation by the GSP-spec module of Gaia/RVS spectra has produced an homogeneous catalogue of about 174,000 AGB stars. Among the 13 chemical elements presented in this catalogue, the abundance of 2 of them (Ce and Nd) have…
We present results from the first large-scale survey of neutron(n)-capture element abundances in planetary nebulae (PNe). This survey was motivated by the fact that a PN may be enriched in n-capture elements if its progenitor star…
Recent spectroscopic measurements in open clusters younger than the Sun, with [Fe/H]>=0, showed that the abundances of neutron-rich elements have continued to increase in the Galaxy after the formation of the Sun, roughly maintaining a…
The low-metallicity RV Tauri star MACHO47.2496.8, recently discovered in the Large Magellanic Cloud, is highly enriched in carbon and heavy elements produced by the slow neutron capture process (s-process), and is most probably a genuine…
Detailed chemical composition studies of stars with enhanced abundances of neutron-capture elements can provide observational constraints for neutron-capture nucleosynthesis studies and clues for understanding their contribution to the…
Post-asymptotic giant branch stars (post-AGB) in binary systems, with typical orbital periods between ~100 to ~1000 days, result from a poorly understood interaction that terminates their precursory AGB phase. The majority of these binaries…