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

    Estimating fundamental parameters of nearby M dwarfs from SPIRou spectra 2022MNRAS.511.1893C
    APOGEE detection of N-rich stars in the tidal tails of Palomar 5 2022MNRAS.510.3727P
    First models of the s process in AGB stars of solar metallicity for the stellar evolutionary code ATON with a novel stable explicit numerical solver 2022A&A...657A..28Y
    The Milky Way bar and bulge revealed by APOGEE and Gaia EDR3 2021A&A...656A.156Q
    Planetary nebulae in Gaia EDR3: Central star identification, properties, and binarity 2021A&A...656A..51G
    Final Targeting Strategy for the Sloan Digital Sky Survey IV Apache Point Observatory Galactic Evolution Experiment 2 North Survey 2021AJ....162..302B
    Ammonia-methane ratios from H-band near-infrared spectra of late-T and Y dwarfs 2021A&A...655L...3M
    AGB Stars and Their Circumstellar Envelopes: An Operative Approach to Computing Their Atmospheres 2021Univ....7..340C
    AGB Stars and Their Circumstellar Envelopes. I. the VULCAN Code 2021Univ....7...80C
    Vinylacetylene synthesis with a low power submerged carbon arc in n-hexane 2021FNCN...29..956C
    Gaia-ESO survey: Lithium abundances in open cluster Red Clump stars 2021A&A...655A..23M
    CAPOS: The bulge Cluster APOgee Survey. I. Overview and initial ASPCAP results 2021A&A...652A.157G
    Double-lined Spectroscopic Binaries in the APOGEE DR16 and DR17 Data 2021AJ....162..184K
    Symbiotic Stars in the Apache Point Observatory Galactic Evolution Experiment Survey: The Case of LIN 358 and SMC N73 (LIN 445a) 2021ApJ...918...19W
    Alternative Strategies to Solve the Stellar Atmosphere Problem 2021POBeo.100...15C
    Testing the Limits of Precise Subgiant Characterization with APOGEE and Gaia: Opening a Window to Unprecedented Astrophysical Studies 2021ApJ...915...19G
    Homogeneous analysis of globular clusters from the APOGEE survey with the BACCHUS code ‑ III. ω Cen 2021MNRAS.505.1645M
    Chemodynamically Characterizing the Jhelum Stellar Stream with APOGEE-2 2021ApJ...913...39S
    APOGEE view of the globular cluster NGC 6544 2021MNRAS.504.3494G
    An enquiry on the origins of N-rich stars in the inner Galaxy based on APOGEE chemical compositions 2021MNRAS.504.1657K
    The APOGEE Data Release 16 Spectral Line List 2021AJ....161..254S
    Orbital Torus Imaging: Using Element Abundances to Map Orbits and Mass in the Milky Way 2021ApJ...910...17P
    Carbon dust in the evolved born-again planetary nebulae A 30 and A 78 2021MNRAS.503.1543T
    Understanding the evolution and dust formation of carbon stars in the Large Magellanic Cloud via the JWST 2021A&A...647A..69M
    The Similarity of Abundance Ratio Trends and Nucleosynthetic Patterns in the Milky Way Disk and Bulge 2021ApJ...909...77G
    The APOGEE Library of Infrared SSP Templates (A-LIST): High-resolution Simple Stellar Population Spectral Models in the H Band 2021AJ....161..167A
    Probing 3D and NLTE models using APOGEE observations of globular cluster stars 2021A&A...647A..24M
    An Intermediate-age Alpha-rich Galactic Population in K2 2021AJ....161..100W
    Atomic data for the Gaia-ESO Survey 2021A&A...645A.106H
    Are extreme asymptotic giant branch stars post-common envelope binaries? 2021MNRAS.502L..35D
    Low-mass low-metallicity AGB stars as an efficient i-process site explaining CEMP-rs stars 2021A&A...645A..61K
    The contribution of N-rich stars to the Galactic stellar halo using APOGEE red giants 2021MNRAS.500.5462H
    Carbon-enhanced metal-poor stars enriched in s-process and r-process elements 2020JApA...41...46K
    Exploring the Galactic Warp through Asymmetries in the Kinematics of the Galactic Disk 2020ApJ...905...49C
    Wide binaries in planetary nebulae with Gaia DR2 2020A&A...644A.173G
    Heavy-element Abundances in P-rich Stars: A New Site for the s-process? 2020ApJ...904L...1M
    Open Cluster Chemical Homogeneity throughout the Milky Way 2020ApJ...903...55P
    The Gaia-ESO Survey: Calibrating the lithium-age relation with open clusters and associations. I. Cluster age range and initial membership selections 2020A&A...643A..71G
    How many components? Quantifying the complexity of the metallicity distribution in the Milky Way bulge with APOGEE 2020MNRAS.499.1037R
    The Gaia-ESO Survey: A new diagnostic for accretion and outflow activity in the young cluster NGC 2264 2020A&A...642A..56B

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