M. Valentini
A5021397891- Stellar, planetary, and galactic studies
- Astronomy and Astrophysical Research
- Gamma-ray bursts and supernovae
- Astrophysics and Star Formation Studies
- Astro and Planetary Science
- Astronomical Observations and Instrumentation
- Pulsars and Gravitational Waves Research
- Astrophysical Phenomena and Observations
- Geophysics and Gravity Measurements
- Crystallization and Solubility Studies
- High-pressure geophysics and materials
- X-ray Diffraction in Crystallography
- Atomic and Subatomic Physics Research
- History and Developments in Astronomy
- Crystallography and molecular interactions
- Galaxies: Formation, Evolution, Phenomena
- Scientific Research and Discoveries
- Calibration and Measurement Techniques
- Advanced Frequency and Time Standards
- Astronomical and nuclear sciences
- Solar and Space Plasma Dynamics
- Radio Astronomy Observations and Technology
- Historical Astronomy and Related Studies
- Advanced Measurement and Metrology Techniques
- Cosmology and Gravitation Theories
Leibniz Institute for Astrophysics Potsdam
2015-2024
University of Trento
2019-2023
Istituto Nazionale di Fisica Nucleare, Trento Institute for Fundamental Physics And Applications
2019-2023
National Institute for Subatomic Physics
2023
Vitenparken
2023
University of Liège
2007-2019
Union astronomique internationale
2017
Centre for Astrophysics of the University of Porto
2017
Laboratoire d’études spatiales et d’instrumentation en astrophysique
2012
Université de Versailles Saint-Quentin-en-Yvelines
2012
Data Release 5 (DR5) of the Radial Velocity Experiment (RAVE) is fifth data release from a magnitude-limited (9< I < 12) survey stars randomly selected in southern hemisphere. The RAVE medium-resolution spectra ($R\sim7500$) covering Ca-triplet region (8410-8795\AA) span complete time frame start observations 2003 to their completion 2013. velocities 520,781 457,588 unique are presented, which 255,922 stellar have parallaxes and proper motions Tycho-Gaia astrometric solution (TGAS) Gaia DR1....
The Gaia-ESO Survey is obtaining high-quality spectroscopic data for about 10^5 stars using FLAMES at the VLT. UVES high-resolution spectra are being collected 5000 FGK-type stars. These analyzed in parallel by several state-of-the-art methodologies. Our aim to present how these analyses were implemented, discuss their results, and describe a final recommended parameter scale defined. We also precision (method-to-method dispersion) accuracy (biases with respect reference values) of...
We combine high-resolution spectroscopic data from APOGEE-2 Survey Data Release 16 (DR16) with broad-band photometric several sources, as well parallaxes {\it Gaia} 2 (DR2). Using the Bayesian isochrone-fitting code {\tt StarHorse}, we derive distances, extinctions and astrophysical parameters for around 388,815 APOGEE stars, achieving typical distance uncertainties of $\sim 6\%$ giants, 2\%$ dwarfs, extinction 0.07$ mag when all information is available, 0.17$ if optical photometry missing....
In the last 15 years different ground-based spectroscopic surveys have been started (and completed) with general aim of delivering stellar parameters and elemental abundances for large samples Galactic stars, complementing Gaia astrometry. Among those surveys, Gaia-ESO Public Spectroscopic Survey (GES), only one performed on a 8m class telescope, was designed to target 100,000 stars using FLAMES ESO VLT (both Giraffe UVES spectrographs), covering all Milky Way populations, special focus open...
Context. The Gaia-ESO Public Spectroscopic Survey is an ambitious project designed to obtain astrophysical parameters and elemental abundances for 100 000 stars, including large representative samples of the stellar populations in Galaxy, a well-defined sample 60 (plus 20 archive) open clusters. We provide internally consistent results calibrated on benchmark stars star clusters, extending across very wide range ages. This provides legacy data set intrinsic value, equally wide-ranging...
Our understanding of how the Galaxy was formed and evolves is severely hampered by lack precise constraints on basic stellar properties such as distances, masses ages. Here, we show that solar-like pulsating red giants represent a well-populated class accurate distance indicators, spanning large age range, which can be used to map date Galactic disc in regions probed observations made CoRoT1 Kepler space telescopes. When combined with photometric constraints, pulsation spectra evolved stars...
We report the discovery of a group apparently young CoRoT red-giant stars exhibiting enhanced [alpha/Fe] abundance ratios (as determined from APOGEE spectra) with respect to Solar values. Their existence is not explained by standard chemical evolution models Milky Way, and shows that chemical-enrichment history Galactic disc more complex. find similar in previously published samples for which isochrone-ages could be robustly obtained, although smaller relative numbers, explain why these have...
With the advent of space missions CoRoT and Kepler, it has become feasible to determine precise asteroseismic masses ages for large samples red-giant stars. In this paper, we present CoRoGEE dataset -- obtained from lightcurves 606 red giant stars in two fields Galactic disc which have been co-observed an ancillary project APOGEE. We used Bayesian parameter estimation code PARAM calculate distances, extinctions, masses, these a homogeneous analysis, resulting relative statistical...
NASA's re-purposed Kepler mission—dubbed K2—has brought new scientific opportunities that were not anticipated for the original mission. One science goal makes optimal use of K2's capabilities, in particular its 360° ecliptic field view, is galactic archaeology—the study evolution Galaxy from fossil stellar record. The thrust this research to exploit high-precision, time-resolved photometry K2 order detect oscillations red giant stars. This asteroseismic information can provide estimates...
Deciphering the assembly history of Milky Way is a formidable task, which becomes possible only if one can produce high-resolution chrono-chemo-kinematical maps Galaxy. Data from large-scale astrometric and spectroscopic surveys will soon provide us with well-defined view current chemo-kinematical structure Way, but enable blurred on temporal sequence that led to present-day As demonstrated by (ongoing) exploitation data pioneering photometric missions CoRoT, Kepler, K2, asteroseismology...
The discovery of lithium-rich giants contradicts expectations from canonical stellar evolution. Here we report on the serendipitous 20 Li-rich observed during Gaia-ESO Survey, which includes first nine giant stars known towards CoRoT fields. Most our have near-solar metallicities and parameters consistent with being before luminosity bump. This is difficult to reconcile deep mixing models proposed explain lithium enrichment, because these can only operate at later evolutionary stages: or...
Using combined asteroseismic and spectroscopic observations of 418 red-giant stars close to the Galactic disc plane (6 kpc $<R_{\rm Gal}\lesssim13$ kpc, $|Z_{\rm Gal}|<0.3$ kpc), we measure age dependence radial metallicity distribution in Milky Way's thin over cosmic time. The slope iron gradient young population ($-0.058\pm0.008$ [stat.] $\pm0.003$ [syst.] dex/kpc) is consistent with recent Cepheid measurements. For stellar populations ages $1-4$ Gyr slightly steeper, at a value...
The Gaia-ESO survey (GES) is now in its fifth and last year of observations, has already produced tens thousands high-quality spectra stars all Milky Way components. This paper presents the strategy behind selection astrophysical calibration targets, ensuring that GES results on radial velocities, atmospheric parameters, chemical abundance ratios will be both internally consistent easily comparable with other literature results, especially from large spectroscopic surveys Gaia. particularly...
Context. In June 2022, Gaia DR3 provided the astronomy community with about one million spectra from Radial Velocity Spectrometer (RVS) covering CaII triplet region. next data releases, we anticipate number of RVS to successively increase several 10 eventually more than 200 spectra. Thus, stellar are projected be produced on an ‘industrial scale’, numbers well above those for current and anticipated ground-based surveys. However, one-third published have 15 ≤ S /N 25 per pixel such that they...
We introduce a novel orbit superposition method designed to reconstruct the stellar density structure, kinematics, and chemical abundance distribution of entire Milky Way by leveraging 6D phase-space information from its resolved populations, limited spatial coverage APOGEE DR17.
A precise characterisation of the red giants in seismology fields CoRoT satellite is a prerequisite for further in-depth seismic modelling. High-resolution FEROS and HARPS spectra were obtained as part ground-based follow-up campaigns 19 targets holding great asteroseismic potential. These data are used to accurately estimate their fundamental parameters abundances 16 chemical species self-consistent manner. Some powerful probes mixing investigated (the Li CNO abundances, well carbon...
Very metal-poor halo stars are the best candidates for being among oldest objects in our Galaxy. Samples of with age determination and detailed chemical composition measurements provide key information constraining nature first stellar generations nucleosynthesis regime.} Age estimates very uncertain available only a small number stars. Here we present results pilot program aimed at deriving precise masses, ages abundances giants using asteroseismology, high-resolution spectroscopy. We...
We report 20 new lithium-rich giants discovered within the Gaia-ESO Survey, including first Li-rich giant with evolutionary stage confirmed by CoRoT data. Atmospheric parameters and abundances were derived in model atmosphere analyses using medium-resolution GIRAFFE or high-resolution UVES spectra. These results are part of fifth internal data release Gaia-ESO. The Li corrected for non-LTE effects. used Gaia DR2 parallaxes to estimate distances luminosities. have A(Li) > 2.2 dex. majority...
Ensemble studies of red-giant stars with exquisite asteroseismic ( Kepler ), spectroscopic (APOGEE), and astrometric Gaia ) constraints offer a novel opportunity to recast address long-standing questions concerning the evolution Galaxy. Here, we infer masses ages for nearly 5400 giants available light curves APOGEE spectra using code PARAM , discuss some systematics that may affect accuracy inferred stellar properties. We then present patterns in mass, evolutionary state, age, chemical...
In a previous paper [arXiv:0712.2391], we presented the selection criteria needed to search for symbiotic stars in IPHAS, INT Halpha survey of Northern Galactic plane. IPHAS gives us opportunity make systematic, complete magnitude-limited volume. Follow-up spectroscopy at different telescopes worldwide sample sixty two star candidates is presented. Seven out nineteen S-type observed spectroscopically are confirmed be genuine stars. The spectral type their red giant components, as well...
Solar-like oscillating giants observed by the space-borne satellites CoRoT and Kepler can be used as key tracers of stellar populations in Milky Way. When combined with additional photometric/spectroscopic constraints, pulsation spectra solar-like giant stars not only reveal their radii, hence distances, but also provide well-constrained estimates masses, which proxies for ages these evolved stars. In this contribution we supplementary material to comparison presented Miglio et al. (2013)...