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

    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
    The Open Cluster Chemical Abundances and Mapping Survey. VI. Galactic Chemical Gradient Analysis from APOGEE DR17 2022AJ....164...85M
    Asphaltenes as model compounds of the UIBs/AIBs detected in various astrophysical objects. Part 3: Petroleum asphaltenes high energy radiation processed 2022FNCN...30..923G
    Asphaltenes as model compounds of the UIBs/AIBs detected in various astrophysical objects. Part 2 – Natural bitumens asphaltenes carbonization 2022FNCN...30..699C
    Chemical Cartography with APOGEE: Mapping Disk Populations with a 2-process Model and Residual Abundances 2022ApJS..260...32W
    Asphaltenes as model compounds of the UIBs/AIBs detected in various astrophysical objects. Part 1 – Petroleum asphaltenes carbonization 2022FNCN...30..571C
    Is Terzan 5 the remnant of a building block of the Galactic bulge? Evidence from APOGEE 2022MNRAS.513.3429T
    The TESS-Keck Survey. XI. Mass Measurements for Four Transiting Sub-Neptunes Orbiting K Dwarf TOI-1246 2022AJ....163..293T
    Estimation of Nitrogen-to-Iron Abundance Ratios from Low-Resolution Spectra 2022JKAS...55...23K
    The Open Cluster Chemical Abundances and Mapping Survey. VII. APOGEE DR17 [C/N]-Age Calibration 2022AJ....163..229S
    Carbon Abundances in Compact Galactic Planetary Nebulae: An Ultraviolet Spectroscopic Study with the Space Telescope Imaging Spectrograph (STIS) 2022ApJ...929..148S
    Survey of Surveys. I. The largest compilation of radial velocities for the Galaxy 2022A&A...659A..95T
    The Seventeenth Data Release of the Sloan Digital Sky Surveys: Complete Release of MaNGA, MaStar, and APOGEE-2 Data 2022ApJS..259...35A
    Quantifying radial migration in the Milky Way: inefficient over short time-scales but essential to the very outer disc beyond 15 kpc 2022MNRAS.511.5639L
    Detailed Chemical Abundances for a Benchmark Sample of M Dwarfs from the APOGEE Survey 2022ApJ...927..123S
    Exploring the S-process History in the Galactic Disk: Cerium Abundances and Gradients in Open Clusters from the OCCAM/APOGEE Sample 2022ApJ...926..154S
    The Influence of 10 Unique Chemical Elements in Shaping the Distribution of Kepler Planets 2022AJ....163..128W

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