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Leda Berni, Lorenzo Spina, Laura Magrini et al. 2025
The paper "Exploring substructures in the Milky Way halo Neural networks applied to Gaia and APOGEE DR 17" by Leda Berni presents a new method to identify stellar streams and accreted structures in the Galactic halo.
Traditional approaches often rely on stellar dynamics, but these can fail when streams lose dynamical coherence due to tidal forces, Galactic plane crossings, and star loss. To overcome this, Leda developed CREEK, an integrated system that combines chemistry and dynamics through advanced machine learning techniques.
CREEK leverages Siamese neural networks, graph neural networks, autoencoders, and the OPTICS algorithm to detect accreted structures in a fully data-driven way.
Applied to the APOGEE dataset, CREEK successfully recovered 80% of globular clusters, re-identified several known stellar streams, and even uncovered a potential new stream.
This work, conducted in collaboration with Lorenzo Spina, Laura Magrini, Davide Massari, José Schiappacasse Ulloa, and Riano Escate Giribaldi, not only provides an objective, data-driven approach to mapping the Milky Way’s assembly history, but also opens new avenues for the next generation of large spectroscopic surveys and dedicated instruments such as WST.
Emanuele Spitoni, Marco Palla, Laura Magrini et al. 2025
In this work, led by Emanuele Spitoni, we explored how stellar migration and gas giants influence the Galactic Habitable Zone — and the results are intriguing.
Turns out, stars on the move can boost habitability in the outer Galaxy, and gas giants might help Earth-like planets form rather than hinder them.
We tested our models using homogeneous stellar parameters, giving us a clearer view of where habitable worlds might emerge.
Schippacasse-Ulloa, J., Magrini, L., Lucatello S., et al. 2025
The article led by Jose Schiappacasse-Ulloa with Laura Magrini, Sofia Randich , Angela Bragaglia, Eugenio Carretta, Gabriele Cescutti, Federico Cescutti, C. Clare Worley, Francesca Lucertini, and Leda Berni, using the calibration sample of globular clusters of the Gaia-ESO survey investigates potential relations between the hot H-burning elements (Na, Al) and neutron-capture elements.
In this work, we also explored the potential differences in the [Eu/Mg] ratio of the globular cluster with in-situ and ex-situ origins, offering clues about their distinct chemical evolution and origins.
Viscasillas Vázquez, C., Magrini, L.; Spitoni, E et al. 2025
Traditionally, the spiral structure of our Galaxy has been traced using stellar density, kinematics, and gas distribution. But recent work suggests that chemical abundances may offer a powerful alternative.
In our latest study, led by Carlos Viscasillas Vazquez with Laura Magrini, Emanuele Spitoni, Gabriele Cescutti, Grazina Tautvaisiene, Arianna Vasini, Sofia Randich, and Giuseppe Germano Sacco, we use data from the Gaia-ESO Survey to trace the inner spiral arms of the Milky Way through variations in [Fe/H] and [Mg/Fe].
Our chemical maps of the inner disc reveal over-densities that align with the Scutum and Sagittarius arms, and even a connecting spur between them. These findings are strongly supported by comparisons with 2D chemical evolution models (Spitoni et al. 2023), highlighting the key role of spiral arm transits in shaping radial and azimuthal abundance patterns.
This work opens a new avenue for exploring the structure and evolution of the inner regions of the Milky Way using stellar chemistry.
Our latest study analyses very metal-poor stars using advanced 3D NLTE models, revealing a tight [Mg/Fe] vs [Fe/H] trend with a key transition at [Fe/H] ≈ -2.8 dex. Our study suggests two possible origins for the chemical sequence in the [Mg/Fe] vs [Fe/H] plane. The stars may have formed within the early Milky Way, which was already the dominant galaxy in its Local Group 12.5 billion years ago, or they may have originated in multiple small galaxies that later merged with the Milky Way. High-precision spectroscopic analysis is essential to tracing the Galaxy’s evolution, and expanding the sample and element analysis will be key to distinguishing between these scenarios.
Our catalogue is online: https://sites.google.com/inaf.it/arielstellarcatalogue
The Ariel space mission, launching in 2029, will study planetary atmospheres around stars of spectral types M to A. To optimize its scientific output, FGK-type stars in the Ariel Tier 1 Mission Candidate Sample (MCS) need to be pre-characterized. This study uses spectral synthesis to analyze fast-rotating FGK stars and EW analysis for slow-rotating stars. Our updated stellar parameters nearly double the number of analyzed MCS hosts to 353 stars. We also confirmed a correlation between stellar mass and giant planet radius, with more inflated planets around stars of lower metallicity, and found that giant planets are more common around metal-rich stars in the thin disc, while lower-mass planets are more frequent in the thick disc.
In this work, we investigated the evolution of abundance gradients in the Milky Way using a large sample of open clusters from the Gaia-ESO survey. After carefully selecting cluster members to avoid biases, we compare the data with chemical evolution models, testing the two-infall and three-infall scenarios. Our results reveal a metallicity decrease in young clusters that the two-infall model cannot explain, while the three-infall model, with a late gas accretion episode, accounts for it—though requiring a milder metal dilution. We propose an extended three-infall framework to describe the entire Galactic disk's chemical evolution.
Chemical clocks based on [s/α] ratios are essential for estimating stellar ages, but these relationships vary across the Milky Way. Current models fail to reproduce the observed increase in [s/α] at young ages, particularly for Ba.
Using a multi-zone chemical evolution model, we explored various scenarios, including gas infall, star formation, and AGB yields, comparing results to Gaia-ESO data. A three-infall model best matches the outer disc trends but struggles with the inner disc, especially for Ba. Ba production must increase by over 50% in the last 3 Gyr to match observations. Current nucleosynthesis calculations cannot fully account for this.
Our results highlight that the [s/α] versus age relation is not universal, with existing models failing to capture the complexity, particularly in the inner disc.
The High-Resolution Multi-Object Spectrograph (HRMOS) is a facility instrument that we plan to propose for the Very Large Telescope (VLT) of the European Southern Observatory (ESO), following the initial presentation at the VLT 2030 workshop held at ESO in June 2019. The science cases presented in this White Paper include topics and ideas developed by the Core Science Team with the contributions from the astronomical community, also through the wide participation in the first HRMOS Workshop that took place in Firenze (Italy) in October 2021.
Van der Swaelmen, M., Viscasillas Vazquez, C., Magrini, L. et al. 2024
We took advantage of the intersections between Gaia RVS and Gaia-ESO to compare their stellar parameters, abundances and radial and rotational velocities. We aimed at verifying the overall agreement between the two datasets, considering the various calibrations and the quality-control flag system suggested for the Gaia GSP-Spec parameters.
This study aims to investigate correlations between the Mean Interdistance, Mean Closest Interdistance and Median Weighted Central Interdistance with the age of star clusters, examining their evolutionary trends and assessing the robustness of these quantities as possible age indicators.
This study aims to investigate whether open clusters and field stars respond differently to the perturbations that cause radial migration. In particular, we aim to understand the nature of the oldest surviving clusters.
We investigate the origin of neutron-capture elements by analysing their abundance patterns and radial gradients in the Galactic thin disc. We adopt a detailed two-infall chemical evolution model for the Milky Way, including state-of-the-art nucleosynthesis prescriptions for neutron-capture elements. We consider r-process nucleosynthesis from merging neutron stars and magneto-rotational supernovae , and s-process synthesis from low- and intermediate-mass stars and rotating massive stars. The predictions of our model are compared with data from the sixth data release of the Gaia-ESO survey.
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