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

    Sensitized Radiation-Induced Polymerization of Indene with 1,1,2,2-Tetrachloroethane
    Technetium-rich M stars: Prime diagnostics of recent third dredge-up events on the asymptotic giant branch 2025A&A...702A..39S
    Investigating Phosphorus Abundances in a Sample of APOGEE-2 Bulge Globular Clusters 2025AJ....170..245B
    Discovery of SiC and Iron Dust around AGB Stars in the Very Metal-poor Sextans a Dwarf Galaxy with JWST: Implications for Dust Production at High Redshift 2025ApJ...991...24B
    Solvent-Free Solid State Dechlorination of C 60 Cl 6 and C 60 Cl 12 with Cesium Iodide 2025FNCN...33..910C
    Roadmap on carbon molecular nanostructures in space 2025EPJD...79...94H
    Deep survey of millimeter radio recombination lines toward the planetary nebulae IC 418 and NGC 7027 2025A&A...700A.194H
    Abundances of P, S, and K in 58 bulge spheroid stars from APOGEE 2025A&A...700A.184B
    JWST observations of the Ring Nebula (NGC 6720) – II. PAH emission 2025MNRAS.540.1984C
    JWST Observations of the Ring Nebula (NGC 6720). III. A Dusty Disk around Its Central Star 2025ApJ...985..101S
    High energy radiation induced degradation of poly(lactic acid) (PLLA) film: radiation chemical yield, kinetics, mechanism and radioracemization evidences 2025JRNC..334.2875C
    Kepler meets Gaia DR3: Homogeneous extinction-corrected color-magnitude diagram and binary classification 2025A&A...696A.243G
    Hexa-(2-ethylhexyl)-hexa-peri-hexabenzocoronene as archetypal model compound of asphaltenes and MAONs
    A comprehensive Gaia view of ellipsoidal and rotational red giant binaries 2025A&A...696A..82N
    Planetary nebulae of the Large Magellanic Cloud: II. The connection with the progenitors' properties 2025A&A...694A.177V
    Detection of binary companions below the diffraction limit with lucky imaging 2025A&A...694A..48C
    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

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