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

    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
    The origin of the planetary nebula M 1-16. A morpho-kinematic and chemical analysis 2023A&A...676A.101G
    The Eighteenth Data Release of the Sloan Digital Sky Surveys: Targeting and First Spectra from SDSS-V 2023ApJS..267...44A
    An investigation of non-canonical mixing in red giant stars using APOGEE <SUP>12</SUP>C/<SUP>13</SUP>C ratios observed in open cluster stars 2023MNRAS.524.4418M
    A Blueprint for the Milky Way's Stellar Populations. IV. A String of Pearls-the Galactic Starburst Sequence 2023ApJ...952...66A
    Stellar Characterization and Radius Inflation of Hyades M-dwarf Stars from the APOGEE Survey 2023ApJ...951...90W
    Catalog of Planetary Nebulae Detected by GALEX and Corollary Optical Surveys 2023ApJS..266...34G
    Two warm Neptunes transiting HIP 9618 revealed by TESS and Cheops 2023MNRAS.523.3069O
    StarHorse results for spectroscopic surveys and Gaia DR3: Chrono-chemical populations in the solar vicinity, the genuine thick disk, and young alpha-rich stars 2023A&A...673A.155Q
    Unveiling the chemical fingerprint of phosphorus-rich stars. I. In the infrared region of APOGEE-2 2023A&A...673A.123B
    The Carbon Star DY Persei May Be a Cool R Coronae Borealis Variable 2023ApJ...948...15G
    A super-Earth and a mini-Neptune near the 2:1 MMR straddling the radius valley around the nearby mid-M dwarf TOI-2096 2023A&A...672A..70P
    A spectral classification system for hydrogen-deficient carbon stars 2023MNRAS.521.1674C
    The chemical characterization of halo substructure in the Milky Way based on APOGEE 2023MNRAS.520.5671H
    The Gaia-ESO survey: Placing constraints on the origin of r-process elements 2023A&A...670A.129V
    The intense production of silicates during the final AGB phases of intermediate mass stars 2023A&A...670A..97M
    Comparative analysis of atmospheric parameters from high-resolution spectroscopic sky surveys: APOGEE, GALAH, Gaia-ESO 2023A&A...670A.107H
    Hydrogenation of [Li@C60]PF6: A comparison with fulleranes derived from C60 2022FNCN...30.1245G
    On the Presence of Metallofullerenes in Fullerene-rich Circumstellar Envelopes 2023ApJ...942....5B
    HD 20329b: An ultra-short-period planet around a solar-type star found by TESS 2022A&A...668A.158M
    The messy death of a multiple star system and the resulting planetary nebula as observed by JWST 2022NatAs...6.1421D
    The Gaia-ESO Public Spectroscopic Survey: Motivation, implementation, GIRAFFE data processing, analysis, and final data products 2022A&A...666A.120G
    The Gaia-ESO Public Spectroscopic Survey: Implementation, data products, open cluster survey, science, and legacy,★ 2022A&A...666A.121R
    Estimating the atmospheric properties of 44 M dwarfs from SPIRou spectra 2022MNRAS.516.3802C
    BACCHUS Analysis of Weak Lines in APOGEE Spectra (BAWLAS) 2022ApJS..262...34H