Examinando por Autor "Spina, L."
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Ítem The Gaia -ESO Survey: Chemical signatures of rocky accretion in a young solar-type star(EDP Sciences, 2015-10) Spina, L.; Palla, F.; Randich, S.; Sacco, G.; Jeffries, R.; Magrini, L.; Franciosini, E.; Meyer, M.R.; Tautvaišiene, G.; Gilmore, G.; Alfaro, E.J.; Allende Prieto, C.; Bensby, T.; Bragaglia, A.; Flaccomio, E.; Koposov, S.E.; Lvanzafame, A.C.; Costado, M.T.; Hourihane, A.; Lardo, C.; Lewis, J.; Monaco, L.; Morbidelli, L.; Sousa, S.G.; Worley, C.C.; Zaggia, S.It is well known that newly formed planetary systems undergo processes of orbital reconfiguration and planetary migration. As a result, planets or protoplanetary objects may accrete onto the central star, being fused and mixed into its external layers. If the accreted mass is sufficiently high and the star has a sufficiently thin convective envelope, such events may result in a modification of the chemical composition of the stellar photosphere in an observable way, enhancing it with elements that were abundant in the accreted mass. The recent Gaia-ESO Survey observations of the 10-20 Myr old Gamma Velorum cluster have enabled identifying a star that is significantly enriched in iron with respect to other cluster members. In this Letter we further investigate the abundance pattern of this star, showing that its abundance anomaly is not limited to iron, but is also present in the refractory elements, whose overabundances are correlated with the condensation temperature. This finding strongly supports the hypothesis of a recent accretion of rocky material. © ESO, 2015.Ítem The Gaia -ESO Survey: The origin and evolution of s -process elements(EDP Sciences, 2018-09) Magrini, L.; Spina, L.; Randich, S.; Friel, E.; Kordopatis, G.; Worley, C.; Pancino, E.; Bragaglia, A.; Donati, P.; Tautvaišienė, G.; Bagdonas, V.; Delgado-Mena, E.; Adibekyan, V.; Sousa, S.G.; Jiménez-Esteban, F.M.; Sanna, N.; Roccatagliata, V.; Bonito, R.; Sbordone, L.; Duffau, S.; Gilmore, G.; Feltzing, S.; Jeffries, R.D.; Vallenari, A.; Alfaro, E.J.; Bensby, T.; Francois, P.; Koposov, S.; Korn, A.J.; Recio-Blanco, A.; Smiljanic, R.; Bayo, A.; Carraro, G.; Casey, A.R.; Costado, M.T.; Damiani, F.; Franciosini, E.; Frasca, A.; Hourihane, A.; Jofré, P.; De Laverny, P.; Lewis, J.; Masseron, T.; Monaco, L.; Morbidelli, L.; Prisinzano, L.; Sacco, G.; Zaggia, S.Context. Several works have found an increase of the abundances of the s-process neutron-capture elements in the youngest Galactic stellar populations. These trends provide important constraints on stellar and Galactic evolution and they need to be confirmed with large and statistically significant samples of stars spanning wide age and distance intervals. Aims. We aim to trace the abundance patterns and the time evolution of five s-process elements - two belonging to the first peak, Y and Zr, and three belonging to the second peak, Ba, La, and Ce - using the Gaia-ESO IDR5 results for open clusters and disc stars. Methods. From the UVES spectra of cluster member stars, we determined the average composition of clusters with ages >0.1 Gyr. We derived statistical ages and distances of field stars, and we separated them into thin and thick disc populations. We studied the time-evolution and dependence on metallicity of abundance ratios using open clusters and field stars whose parameters and abundances were derived in a homogeneous way. Results. Using our large and homogeneous sample of open clusters, thin and thick disc stars, spanning an age range larger than 10 Gyr, we confirm an increase towards young ages of s-process abundances in the solar neighbourhood. These trends are well defined for open clusters and stars located nearby the solar position and they may be explained by a late enrichment due to significant contribution to the production of these elements from long-living low-mass stars. At the same time, we find a strong dependence of the s-process abundance ratios on the Galactocentric distance and on the metallicity of the clusters and field stars. Conclusions. Our results, derived from the largest and most homogeneous sample of s-process abundances in the literature, confirm the growth with decreasing stellar ages of the s-process abundances in both field and open cluster stars. At the same time, taking advantage of the abundances of open clusters located in a wide Galactocentric range, these results offer a new perspective on the dependence of the s-process evolution on the metallicity and star formation history, pointing to different behaviours at various Galactocentric distances. © 2018 ESO.Ítem The Gaia-ESO Public Spectroscopic Survey: Implementation, data products, open cluster survey, science, and legacy(EDP Sciences, 2022-10-01) Randich, S.; Gilmore, G.; Magrini, L.; Sacco, G.G.; Jackson, R.J.; Jeffries, R.D.; Worley, C.C.; Hourihane, A.; Gonneau, A.; Viscasillas Vázquez, C.; Franciosini, E.; Lewis, J.R.; Alfaro, E.J.; Allende Prieto, C.; Bensby, T.; Blomme, R.; Bragaglia, A.; Flaccomio, E.; François, P.; Irwin, M.J.; Koposov, S.E.; Korn, A.J.; Lanzafame, A.C.; Pancino, E.; Recio Blanco, A.; Smiljanic, R.; Van Eck, S.; Zwitter, T.; Asplund, M.; Bonifacio, P.; Feltzing, S.; Binney, J.; Drew, J.; Ferguson, A.M.N.; Micela, G.; Negueruela, I.; Prusti, T.; Rix, H.-W.; Vallenari, A.; Bayo, A.; Bergemann, M.; Biazzo, K.; Carraro, G.; Casey, A.R.; Damiani, F.; Frasca, A.; Heiter, U.; Hill, V.; Jofré, P.; de Laverny, P.; Lind, K.; Marconi, G.; Martayan, C.; Masseron, T.; Monaco, L.; Morbidelli, L.; Prisinzano, L.; Sbordone, L.; Sousa, S.G.; Zaggia, S.; Adibekyan, V.; Bonito, R.; Caffau, E.; Daflon, S.; Feuillet, D.K.; Gebran, M.; González Hernández, J.I.; Guiglion, G.; Herrero, A.; Lobel, A.; Maíz Apellániz, J.; Merle, T.; Mikolaitis, S.; Montes, D.; Morel, T.; Soubiran, C.; Spina, L.; Tabernero, H.M.; Tautvaišiene, G.; Traven, G.; Valentini, M.; Van der Swaelmen, M.; Villanova, S.; Wright, N.J.; Abbas, U.; Aguirre Børsen-Koch, V.; Alves, J.; Balaguer Núnez, L.; Barklem, P.S.; Barrado, D.; Berlanas, S.R.; Binks, A.S.; Bressan, A.; Capuzzo Dolcetta, R.; Casagrande, L.; Casamiquela, L.; Collins, R.S.; D’Orazi, V.; Dantas, M.L.L.; Debattista, V.P.; Delgado Mena, E.; Di Marcantonio, P.; Drazdauskas, A.; Evans, N.W.; Famaey, B.; Franchini, M.; Frémat, Y.; Friel, E.D.; Fu, X.; Geisler, D.; Gerhard, O.; González Solares, E.A.; Grebel, E.K.; Gutiérrez Albarrán, M.L.; Hatzidimitriou, D.; Held, E.V.; Jiménez Esteban, F.; Jönsson, H.; Jordi, C.; Khachaturyants, T.; Kordopatis, G.; Kos, J.; Lagarde, N.; Mahy, L.; Mapelli, M.; Marfil, E.; Martell, S.L.; Messina, S.; Miglio, A.; Minchev, I.; Moitinho, A.; Montalban, J.; Monteiro, M.J.P.F.G.; Morossi, C.; Mowlavi, N.; Mucciarelli, A.; Murphy, D.N.A.; Nardetto, N.; Ortolani, S.; Paletou, F.; Palous, J.; Paunzen, E.; Pickering, J.C.; Quirrenbach, A.; Re Fiorentin, P.; Read, J.I.; Romano, D.; Ryde, N.; Sanna, N.; Santos, W.; Seabroke, G.M.; Spagna, A.; Steinmetz, M.; Stonkuté, E.; Sutorius, E.; Thévenin, F.; Tosi, M.; Tsantaki, M.; Vink, J.S.; Wright, N.; Wyse, R.F.G.; Zoccali, M.; Zorec, J.; Zucker, D.B.; Walton, N.A.Context. In the last 15 years different ground-based spectroscopic surveys have been started (and completed) with the general aim of delivering stellar parameters and elemental abundances for large samples of Galactic stars, complementing Gaia astrometry. Among those surveys, the Gaia-ESO Public Spectroscopic Survey, the only one performed on a 8m class telescope, was designed to target 100 000 stars using FLAMES on the ESO VLT (both Giraffe and UVES spectrographs), covering all the Milky Way populations, with a special focus on open star clusters. Aims. This article provides an overview of the survey implementation (observations, data quality, analysis and its success, data products, and releases), of the open cluster survey, of the science results and potential, and of the survey legacy. A companion article reviews the overall survey motivation, strategy, Giraffe pipeline data reduction, organisation, and workflow. Methods. We made use of the information recorded and archived in the observing blocks; during the observing runs; in a number of relevant documents; in the spectra and master catalogue of spectra; in the parameters delivered by the analysis nodes and the working groups; in the final catalogue; and in the science papers. Based on these sources, we critically analyse and discuss the output and products of the Survey, including science highlights. We also determined the average metallicities of the open clusters observed as science targets and of a sample of clusters whose spectra were retrieved from the ESO archive. Results. The Gaia-ESO Survey has determined homogeneous good-quality radial velocities and stellar parameters for a large fraction of its more than 110 000 unique target stars. Elemental abundances were derived for up to 31 elements for targets observed with UVES. Lithium abundances are delivered for about 1/3 of the sample. The analysis and homogenisation strategies have proven to be successful; several science topics have been addressed by the Gaia-ESO consortium and the community, with many highlight results achieved. Conclusions. The final catalogue will be released through the ESO archive in the first half of 2022, including the complete set of advanced data products. In addition to these results, the Gaia-ESO Survey will leave a very important legacy, for several aspects and for many years to come. © ESO 2022.Ítem The Gaia-ESO Public Spectroscopic Survey: Motivation, implementation, GIRAFFE data processing, analysis, and final data products?(EDP Sciences, 2022-10-01) Gilmore, G.; Randich, S.; Worley, C.C.; Hourihane, A.; Gonneau, A.; Sacco, G.G.; Lewis, J.R.; Magrini, L.; François, P.; Jeffries, R.D.; Koposov, S.E.; Bragaglia, A.; Alfaro, E.J.; Allende Prieto, C.; Blomme, R.; Korn, A.J.; Lanzafame, A.C.; Pancino, E.; Recio Blanco, A.; Smiljanic, R.; Van Eck, S.; Zwitter, T.; Bensby, T.; Flaccomio, E.; Irwin, M.J.; Franciosini, E.; Morbidelli, L.; Damiani, F.; Bonito, R.; Friel, E.D.; Vink, J.S.; Prisinzano, L.; Abbas, U.; Hatzidimitriou, D.; Held, E.V.; Jordi, C.; Paunzen, E.; Spagna, A.; Jackson, R.J.; Maíz Apellániz, J.; Asplund, M.; Bonifacio, P.; Feltzing, S.; Binney, J.; Drew, J.; Ferguson, A.M.N.; Micela, G.; Negueruela, I.; Prusti, T.; Rix, H.-W.; Vallenari, A.; Bergemann, M.; Casey, A.R.; Laverny, P.; Frasca, A.; Hill, V.; Lind, K.; Sbordone, L.; Sousa, S.G.; Adibekyan, V.; Caffau, E.; Daflon, S.; Feuillet, D.K.; Gebran, M.; González Hernández, J.I.; Guiglion, G.; Herrero, A.; Lobel, A.; Merle, T.; Mikolaitis, S.; Montes, D.; Morel, T.; Ruchti, G.; Soubiran, C.; Tabernero, H.M.; Tautvaišiene, G.; Traven, G.; Valentini, M.; Van der Swaelmen, M.; Villanova, S.; Viscasillas Vázquez, C.; Bayo, A.; Biazzo, K.; Carraro, G.; Edvardsson, B.; Heiter, U.; Jofré, P.; Marconi, G.; Martayan, C.; Masseron, T.; Monaco, L.; Walton, N.A.; Zaggia, S.; Aguirre Børsen-Koch, V.; Alves, J.; Balaguer Núnez, L.; Barklem, P.S.; Barrado, D.; Bellazzini, M.; Berlanas, S.R.; Binks, A.S.; Bressan, A.; Capuzzo Dolcetta, R.; Casagrande, L.; Casamiquela, L.; Collins, R.S.; D’Orazi, V.; Dantas, M.L.L.; Debattista, V.P.; Delgado Mena, E.; Marcantonio, P. Di; Drazdauskas, A.; Evans, N.W.; Famaey, B.; Franchini, M.; Frémat, Y.; Fu, X.; Geisler, D.; Gerhard, O.; González Solares, E.A.; Grebel, E.K.; Albarrán Gutiérrez, M.L.; Jiménez Esteban, F.; Jönsson, H.; Khachaturyants, T.; Kordopatis, G.; Kos, J.; Lagarde, N.; Ludwig, H.-G.; Mahy, L.; Mapelli, M.; Marfil, E.; Martell, S.L.; Messina, S.; Miglio, A.; Minchev, I.; Moitinho, A.; Montalban, J.; Monteiro, M.J.P.F.G.; Morossi, C.; Mowlavi, N.; Mucciarelli, A.; Murphy, D.N.A.; Nardetto, N.; Ortolani, S.; Paletou, F.; Palous, J.; Pickering, J.C.; Quirrenbach, A.; Re Fiorentin, P.; Read, J.I.; Romano, D.; Ryde, N.; Sanna, N.; Santos, W.; Seabroke, G.M.; Spina, L.; Steinmetz, M.; Stonkuté, E.; Sutorius, E.; Thévenin, F.; Tosi, M.; Tsantaki, M.; Wright, N.; Wyse, R.F.G.; Zoccali, M.; Zorec, J.; Zucker, D.B.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 the Galaxy, and a well-defined sample of 60 (plus 20 archive) open clusters. We provide internally consistent results calibrated on benchmark stars and star clusters, extending across a very wide range of abundances and ages. This provides a legacy data set of intrinsic value, and equally a large wide-ranging dataset that is of value for the homogenisation of other and future stellar surveys and Gaia’s astrophysical parameters. Aims. This article provides an overview of the survey methodology, the scientific aims, and the implementation, including a description of the data processing for the GIRAFFE spectra. A companion paper introduces the survey results. Methods. Gaia-ESO aspires to quantify both random and systematic contributions to measurement uncertainties. Thus, all available spectroscopic analysis techniques are utilised, each spectrum being analysed by up to several different analysis pipelines, with considerable effort being made to homogenise and calibrate the resulting parameters. We describe here the sequence of activities up to delivery of processed data products to the ESO Science Archive Facility for open use. Results. The Gaia-ESO Survey obtained 202 000 spectra of 115 000 stars using 340 allocated VLT nights between December 2011 and January 2018 from GIRAFFE and UVES. Conclusions. The full consistently reduced final data set of spectra was released through the ESO Science Archive Facility in late 2020, with the full astrophysical parameters sets following in 2022. A companion article reviews the survey implementation, scientific highlights, the open cluster survey, and data products. © G. Gilmore et al. 2022.Ítem The Gaia-ESO survey: the non-universality of the age–chemical-clocks–metallicity relations in the Galactic disc(EDP Sciences, 2020-07) Casali, G.; Spina, L.; Magrini, L.; Karakas, A. I.; Kobayashi, C.; Feltzing, S.; Van der Swaelmen, M.; Tsantaki, M.; Jofré, P.; Bragaglia, A.; Feuille, D.; . Bensby, T; Biazzo, K.; Gonneau, A; Tautvaišiene˙, G.; Baratella, M; Roccatagliata, V.; Pancino, E.; Sousa, S.; Adibekyan, V.; Martell, S; Bayo, A.; Jackson, R. J.; Jeffries, R. D.; Gilmore, G.; Randich, S.; Alfaro, E.; Koposov, S. E.; Korn, A. J.; Recio-Blanco, A.; Smiljanic, R; . Franciosini, E; Hourihane, A.; Monaco, L.; Morbidelli, L.; Sacco, G.; Worley, C.; Zaggia, S.Context. In the era of large spectroscopic surveys, massive databases of high-quality spectra coupled with the products of the Gaia satellite provide tools to outline a new picture of our Galaxy. In this framework, an important piece of information is provided by our ability to infer stellar ages, and consequently to sketch a Galactic timeline. Aims. We aim to provide empirical relations between stellar ages and abundance ratios for a sample of stars with very similar stellar parameters to those of the Sun, namely the so-called solar-like stars. We investigate the dependence on metallicity, and we apply our relations to independent samples, that is, the Gaia-ESO samples of open clusters and of field stars. Methods. We analyse high-resolution and high-signal-to-noise-ratio HARPS spectra of a sample of solar-like stars to obtain precise determinations of their atmospheric parameters and abundances for 25 elements and/or ions belonging to the main nucleosynthesis channels through differential spectral analysis, and of their ages through isochrone fitting. Results. We investigate the relations between stellar ages and several abundance ratios. For the abundance ratios with a steeper dependence on age, we perform multivariate linear regressions, in which we include the dependence on metallicity, [Fe/H]. We apply our best relations to a sample of open clusters located from the inner to the outer regions of the Galactic disc. Using our relations, we are able to recover the literature ages only for clusters located at RGC > 7 kpc. The values that we obtain for the ages of the inner-disc clusters are much greater than the literature ones. In these clusters, the content of neutron capture elements, such as Y and Zr, is indeed lower than expected from chemical evolution models, and consequently their [Y/Mg] and [Y/Al] are lower than in clusters of the same age located in the solar neighbourhood. With our chemical evolution model and a set of empirical yields, we suggest that a strong dependence on the star formation history and metallicity-dependent stellar yields of s-process elements can substantially modify the slope of the [s/α]–[Fe/H]–age relation in different regions of the Galaxy. Conclusions. Our results point towards a non-universal relation [s/α]–[Fe/H]–age, indicating the existence of relations with different slopes and intercepts at different Galactocentric distances or for different star formation histories. Therefore, relations between ages and abundance ratios obtained from samples of stars located in a limited region of the Galaxy cannot be translated into general relations valid for the whole disc. A better understanding of the s-process at high metallicity is necessary to fully understand the origin of these variations