Start year
1986
Organizational Unit
Organizing institutions
Related grants:
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.
Members
Principal investigator
Domingo Aníbal
García Hernández
Project staff
Arturo
Manchado Torres
Thomas
Masseron
Olga María
Zamora Sánchez
LUCIO
CRIVELLARI
Collaborators
Dr.
P. García Lario
Dr.
G. García Segura
Dr.
L. Stanghellini
Dr.
E. Villaver
Carlos
Allende Prieto
Jorge
García Rojas
Dr.
B. Plez
Dr.
A. Karakas
Dr.
M. Lugaro
Dr.
D. Lambert
Dr.
P. Ventura
Dr.
F. Cataldo
Dr.
Andres Yague
Dr.
Sun Kwok
Dr.
R. Szczerba
Dr.
J.M. Trigo Rodríguez
Dr.
K. Rao
S. Sadjadi
M. Manteiga
C. Dafonte
R. Santoveña
L. Bianchi
Sz. Mészáros
S. Cristallo
L. Piersanti
Results
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.
Scientific activity
Related publications
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Abundances of iron-peak elements in 58 bulge spheroid stars from APOGEEContext. Stars presently identified in the bulge spheroid are probably very old, and their abundances can be interpreted as due to the fast chemical enrichment of the early Galactic bulge. The abundances of the iron-peak elements are important tracers of nucleosynthesis processes, in particular oxygen burning, silicon burning, the weak s-processBarbuy, B. et al.
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112024 -
Dehydrogenation, polymerization and self-assembly in the inhibition of copper surfaces by an ultrathin imidazole filmHere we present a joint experimental-theoretical study on the deposition of imidazole molecules on a Cu(100) surface. X-ray photoelectron spectroscopy (XPS) and Surface-enhanced Raman spectroscopy (SERS) have been carried out on samples prepared upon deposition of sublimated imidazole molecules in ultra-high vacuum (UHV). Computational studiesBarzaga, R. et al.
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Constraining the overcontact phase in massive binary evolution: III. Period stability of known B+B and O+B overcontact systemsContext. Binary systems play a crucial role in massive star evolution. Systems composed of B-type and O-type stars are of particular interest due to their potential to lead to very energetic phenomena or the merging of exotic compact objects. Aims. We aim to determine the orbital period variations of a sample of B+B and O+B massive overcontactVrancken, Jasmine et al.
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Full Abundance Study of Two Newly Discovered Barium GiantsBarium (Ba) stars are chemically peculiar stars that show enhanced surface abundances of heavy elements produced by the slow-neutron-capture process, the so-called s-process. These stars are not sufficiently evolved to undergo the s-process in their interiors, so they are considered products of binary interactions. Ba stars form when a formerVitali, Sara et al.
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Unveiling the chemical fingerprint of phosphorus-rich stars: II. Heavy-element abundances from UVES/VLT spectraContext. The atmospheres of phosphorus-rich (P-rich) stars have been shown to contain between 10 and 100 times more P than our Sun. Given its crucial role as an essential element for life, it is especially necessary to uncover the origin of P-rich stars to gain insights into the still unknown nucleosynthetic formation pathways of P in our GalaxyLugaro, Maria et al.
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102024 -
Neutron decay anomaly, neutron stars, and dark matterThe discrepancies in different measurements of the lifetime of isolated neutrons could be resolved by considering an extra neutron decay channel into dark matter, with a branching ratio of the order of O ( 1 % ). Although the decay channel into a dark fermion χ plus visible matter has already been experimentally excluded, a dark decay with either aBastero-Gil, Mar et al.
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SpectroTranslator: Deep-neural network algorithm for homogenising spectroscopic parametersContext. In modern Galactic astronomy, stellar spectroscopy plays a pivotal role in complementing large photometric and astrometric surveys and enabling deeper insights to be gained into the chemical evolution and chemo-dynamical mechanisms at play in the Milky Way and its satellites. Nonetheless, the use of different instruments and dedicatedThomas, G. F. et al.
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Mass determination of two Jupiter-sized planets orbiting slightly evolved stars: TOI-2420 b and TOI-2485 bContext. Hot and warm Jupiters might have undergone the same formation and evolution path, but the two populations exhibit different distributions of orbital parameters. This challenges our understanding of their actual origin. Aims. We report the results of our warm Jupiters survey, which was carried out with the CHIRON spectrograph within theCarleo, Ilaria et al.
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Solid state debromination of C 60 Br 24 back to C 60 with cesium iodide: kinetics, thermodynamics and mechanismThe bromofullerene C60Br24 undergoes a complete and quantitative debromination to C60 when it is mixed and ground in the solid state with cesium iodide (CsI). The kinetics of this unique solid state debromination reaction was studied with FT-IR spectroscopy on C60Br24 embedded in CsI pellet. The debromination rate constant was measured k = 8.4 x 10Barzaga, Ransel et al.
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32024 -
Green, solventless debromination of C 70 Br 10 to C 70 with CsIA smooth, solventless and solid state debromination of C70Br10 can be achieved in a CsI matrix with the restoration of the pristine C70 in quantitative yields. Such debromination reaction was studied with FT-IR spectroscopy and its kinetics was fitted by a pseudofirst order law, with a rate constant in the range of 3.6-5.2 x 10−5 s−1. The thermalBarzaga, Ransel et al.
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82024 -
A search for Galactic post-asymptotic giant branch stars in Gaia DR3Context. When low- and intermediate-mass stars leave the asymptotic giant branch (AGB) phase, and before they reach the planetary nebula stage, they enter a very brief and rather puzzling stellar evolutionary stage called post-AGB stage. The post-AGB phase lasts very briefly, about a few thousand years at most. The number of objects that areGonzález-Santamaría, I. et al.
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82024 -
Chemical Cartography with APOGEE: Two-process Parameters and Residual Abundances for 288,789 Stars from Data Release 17Stellar abundance measurements are subject to systematic errors that induce extra scatter and artificial correlations in elemental abundance patterns. We derive empirical calibration offsets to remove systematic trends with surface gravity in 17 elemental abundances of 288,789 evolved stars from the SDSS APOGEE survey. We fit these correctedSit, Tawny et al.
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82024 -
An impressionist view of V Hydrae. When MATISSE paints asymmetric giant blobsContext. Asymptotic giant branch (AGB) stars enrich the interstellar medium through their mass loss. The mechanism(s) shaping the circumstellar environment of mass-losing stars is not clearly understood so far. Aims: Our purpose is to study the effect of binary companions located within the first 10 stellar radii from the primary AGB star. In thisPlanquart, L. et al.
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Planetary nebulae of the Large Magellanic Cloud. I. A multiwavelength analysisContext. Planetary nebulae (PNe) have three main components: a central star (CS), ionized gas, and dust in the nebula. Each contains critical chemical fingerprints of the PN's evolution, which serve as tracers of the evolution, nucleosynthesis, and dust production that occurred during the preceding asymptotic giant branch (AGB) phase. Aims: We aimTosi, S. et al.
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82024 -
A hot-Jupiter progenitor on a super-eccentric retrograde orbitGiant exoplanets orbiting close to their host stars are unlikely to have formed in their present configurations 1. These `hot Jupiter' planets are instead thought to have migrated inward from beyond the ice line and several viable migration channels have been proposed, including eccentricity excitation through angular-momentum exchange with a thirdGupta, Arvind F. et al.
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82024 -
CHEOPS in-flight performance. A comprehensive look at the first 3.5 yr of operationsContext. Since the discovery of the first exoplanet almost three decades ago, the number of known exoplanets has increased dramatically. By beginning of the 2000s it was clear that dedicated facilities to advance our studies in this field were needed. The CHaracterising ExOPlanet Satellite (CHEOPS) is a space telescope specifically designed toFortier, A. et al.
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Detection of extragalactic magnetic massive starsContext. Studies of the magnetic characteristics of massive stars have recently received significant attention because they are progenitors of highly magnetised compact objects. Stars initially more massive than about 8 M ⊙ leave behind neutron stars and black holes by the end of their evolution. The merging of binary compact remnant systemsHubrig, S. et al.
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62024 -
High-resolution Spectroscopic Reconnaissance of a Temperate Sub-NeptuneThe study of temperate sub-Neptunes is the new frontier in exoplanetary science. A major development in the past year has been the first detection of carbon-bearing molecules in the atmosphere of a temperate sub-Neptune, K2-18 b, a possible Hycean world, with the James Webb Space Telescope (JWST). The JWST is poised to characterize the atmospheresCabot, Samuel H. C. et al.
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A Perspective on the Milky Way Bulge Bar as Seen from the Neutron-capture Elements Cerium and Neodymium with APOGEEThis study probes the chemical abundances of the neutron-capture elements cerium and neodymium in the inner Milky Way from an analysis of a sample of ∼2000 stars in the Galactic bulge bar spatially contained within ∣X Gal∣ < 5 kpc, ∣Y Gal∣ < 3.5 kpc, and ∣Z Gal∣ < 1 kpc, and spanning metallicities between ‑2.0 ≲ [Fe/H] ≲ +0.5. We classify theSales-Silva, J. V. et al.
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The first measurements of carbon isotopic ratios in post-RGB stars: SZ Mon and DF CygDusty post-red giant branch (post-RGB) stars are low- and intermediate-mass stars where the RGB evolution was prematurely terminated by a poorly understood binary interaction. These binary stars are considered to be low-luminosity analogues of post-asymptotic giant branch (post-AGB) binary stars. In this study, we investigated the chemicalMohorian, Maksym et al.
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52024
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