Nucleosynthesis and molecular processes in the late stages of Stellar Evolution

    General
    Description

    Low- to intermediate-mass (M < 8 solar masses, Ms) stars represent the majority of stars in the Cosmos. They finish their lives on the Asymptotic Giant Branch (AGB) - just before they form planetary nebulae (PNe) - where they experience complex nucleosynthetic and molecular processes. AGB stars are important contributors to the enrichment of the interstellar medium where new stars/planets are born (including our own Early Solar System, ESS), and to the chemical evolution of stellar systems like globular clusters (GCs) and galaxies. In particular, the more massive (M > 4-5 Ms) AGB stars synthesize very different (radio)isotopes from those formed by lower mass AGB stars and Supernova detonations, as a consequence of different nucleosynthesis mechanisms. Evolved stars in the transition phase between AGB stars and PNe also form diverse organic compounds like PAHs, and fullerene and graphene molecular nanostructures, being a wonderful laboratory for Astrochemistry. On-going massive surveys like SDSS-IV/APOGEE-2 and the upcoming James Webb Space Telescope (JWST) represent a fundamental step forward to understand the nucleosynthesis and molecular processes in evolved stars. We aim to explore the nucleosynthesis of light and heavy (radio)isotopes in AGB stars and how they contribute to the ESS radioactive inventory as well as to the formation and evolution of GCs and galaxies. We also aim at understanding the top-down formation process of fullerene and graphene molecular nanostructures in evolved stars. Finally, it is intended to perform data mining with the Gaia satellite, in order to study the AGB- PNe evolutionary phase. In addition we aim to use the GALEX database to discover binary central stars in Galactic PNe.

    Principal investigator

    1. During 2020, we have published 37 papers in high-impact international refereed astronomical journals (including one invited review) and 2 papers in the Chemistry -Physics journal FNCN.

    2. Phosphorus-rich stars with an extremely peculiar chemical abundance pattern have been discovered for the first time, challenging the theoretical nucleosynthesis predictions.

    3. It was demonstrated that the P-rich star progenitors represent a new site for s-process nucleosynthesis, with important implications for the chemical evolution of our Galaxy.

    Related publications

    Abundances of iron-peak elements in 58 bulge spheroid stars from APOGEE 2024A&A...691A.296B
    Dehydrogenation, polymerization and self-assembly in the inhibition of copper surfaces by an ultrathin imidazole film 2024Corro.23512168B
    Constraining the overcontact phase in massive binary evolution: III. Period stability of known B+B and O+B overcontact systems 2024A&A...691A.150V
    Full Abundance Study of Two Newly Discovered Barium Giants 2024ApJ...975...47V
    Unveiling the chemical fingerprint of phosphorus-rich stars: II. Heavy-element abundances from UVES/VLT spectra 2024A&A...690A.262B
    Neutron decay anomaly, neutron stars, and dark matter 2024PhRvD.110h3003B
    SpectroTranslator: Deep-neural network algorithm for homogenising spectroscopic parameters 2024A&A...690A..54T
    Mass determination of two Jupiter-sized planets orbiting slightly evolved stars: TOI-2420 b and TOI-2485 b 2024A&A...690A..18C
    A study on poly(indene)
    Metallofullerenes as potential candidates for the explanation of astrophysical phenomena
    Solid state debromination of C 60 Br 24 back to C 60 with cesium iodide: kinetics, thermodynamics and mechanism 2024FNCN...32..274B
    Green, solventless debromination of C 70 Br 10 to C 70 with CsI 2024FNCN...32..740B
    A search for Galactic post-asymptotic giant branch stars in Gaia DR3 2024A&A...688A.209G
    Chemical Cartography with APOGEE: Two-process Parameters and Residual Abundances for 288,789 Stars from Data Release 17 2024ApJ...970..180S
    An impressionist view of V Hydrae. When MATISSE paints asymmetric giant blobs 2024A&A...687A.306P
    Planetary nebulae of the Large Magellanic Cloud. I. A multiwavelength analysis 2024A&A...688A..36T
    A hot-Jupiter progenitor on a super-eccentric retrograde orbit 2024Natur.632...50G
    CHEOPS in-flight performance. A comprehensive look at the first 3.5 yr of operations 2024A&A...687A.302F
    Detection of extragalactic magnetic massive stars 2024A&A...686L...4H
    High-resolution Spectroscopic Reconnaissance of a Temperate Sub-Neptune 2024ApJ...966L..10C
    A Perspective on the Milky Way Bulge Bar as Seen from the Neutron-capture Elements Cerium and Neodymium with APOGEE 2024ApJ...965..119S
    The first measurements of carbon isotopic ratios in post-RGB stars: SZ Mon and DF Cyg 2024MNRAS.530..761M
    Revisiting the warm sub-Saturn TOI-1710b. The impact of stellar activity on the mass measurement 2024A&A...684A..96O
    On the radiation-induced polymerization of indene: from laboratory study to astrochemical implications 2024JRNC..333..865B
    Complex K: Supernova Origin of Anomalous-velocity H I Structure 2024ApJ...963...87V
    Hydrogenated amorphous carbon grains as an alternative carrier of the 9-13 μm plateau feature in the fullerene planetary nebula Tc 1 2024A&A...682L..18G
    A dynamic view of V Hydrae. Monitoring of a spectroscopic-binary AGB star with an alkaline jet 2024A&A...682A.143P
    JWST observations of the Ring Nebula (NGC 6720): I. Imaging of the rings, globules, and arcs 2024MNRAS.528.3392W
    An ultraviolet spectral study of fullerene-rich planetary nebulae 2024MNRAS.528.2871G
    MELCHIORS. The Mercator Library of High Resolution Stellar Spectroscopy 2024A&A...681A.107R
    Infrared Spectral Fingerprint of Neutral and Charged Endo- and Exohedral Metallofullerenes 2023ApJS..269...26B
    Dust from evolved stars: a pilot analysis of the AGB to PN transition 2023MNRAS.526.5386D
    Measuring small-scale magnetic fields of 44 M dwarfs from SPIRou spectra with ZeeTurbo 2023MNRAS.526.5648C
    GJ 806 (TOI-4481): A bright nearby multi-planetary system with a transiting hot low-density super-Earth 2023A&A...678A..80P
    Light elements Na and Al in 58 bulge spheroid stars from APOGEE 2023MNRAS.526.2365B
    Thermochemical properties of C60Br24 2023FNCN...31..505C
    Fullerene-indene adducts (ICMA &amp; ICBA) in an astrochemical perspective part 1: chemical thermodynamics, stability and electronic absorption spectroscopy 2023FNCN...31..897G
    Fullerene-indene adducts (ICMA &amp; ICBA) in an astrochemical perspective. Part 2: FT-IR spectroscopy from −180 °C to +250 °C 2023FNCN...31..989G
    Synthesis of a new C60 cyanofullerene derivative 2023FNCN...31..695C
    TESS discovery of a super-Earth orbiting the M-dwarf star TOI-1680 2023A&A...677A..31G

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