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6 results on '"Chiappini, C"'

1. Exploring the S-process History in the Galactic Disk: Cerium Abundances and Gradients in Open Clusters from the OCCAM/APOGEE Sample.

Author

Sales-Silva, J. V., Daflon, S., Cunha, K., Souto, D., Smith, V. V., Chiappini, C., Donor, J., Frinchaboy, P. M., García-Hernández, D. A., Hayes, C., Majewski, S. R., Masseron, T., Schiavon, R. P., Weinberg, D. H., Beaton, R. L., Fernández-Trincado, J. G., Jönsson, H., Lane, R. R., Minniti, D., and Manchado, A.

Subjects
CERIUM, INTERSTELLAR medium, STELLAR spectra, OPEN clusters of stars, NUCLEOSYNTHESIS
Abstract

The APOGEE Open Cluster Chemical Abundances and Mapping survey is used to probe the chemical evolution of the s-process element cerium in the Galactic disk. Cerium abundances were derived from measurements of Ce ii lines in the APOGEE spectra using the Brussels Automatic Code for Characterizing High Accuracy Spectra in 218 stars belonging to 42 open clusters. Our results indicate that, in general, for ages < 4 Gyr, younger open clusters have higher [Ce/Fe] and [Ce/α-element] ratios than older clusters. In addition, metallicity segregates open clusters in the [Ce/X]–age plane (where X can be H, Fe, or the α-elements O, Mg, Si, or Ca). These metallicity-dependent relations result in [Ce/Fe] and [Ce/α] ratios with ages that are not universal clocks. Radial gradients of [Ce/H] and [Ce/Fe] ratios in open clusters, binned by age, were derived for the first time, with d[Ce/H]/dRGC being negative, while d[Ce/Fe]/dRGC is positive. [Ce/H] and [Ce/Fe] gradients are approximately constant over time, with the [Ce/Fe] gradient becoming slightly steeper, changing by ∼+0.009 dex kpc−1 Gyr−1. Both the [Ce/H] and [Ce/Fe] gradients are shifted to lower values of [Ce/H] and [Ce/Fe] for older open clusters. The chemical pattern of Ce in open clusters across the Galactic disk is discussed within the context of s-process yields from asymptotic giant branch (AGB) stars, gigayear time delays in Ce enrichment of the interstellar medium, and the strong dependence of Ce nucleosynthesis on the metallicity of its AGB stellar sources. [ABSTRACT FROM AUTHOR]

Published
2022
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2. A NEW STELLAR CHEMO-KINEMATIC RELATION REVEALS THE MERGER HISTORY OF THE MILKY WAY DISK

Author

Minchev, I., Chiappini, C., Martig, M., Steinmetz, M., de Jong, R. S., Boeche, C., Scannapieco, C., Zwitter, T., Wyse, R. F. G., Binney, J. J., Bland-Hawthorn, J., Bienaymé, O., Famaey, B., Freeman, K. C., Gibson, Bradley Kenneth, Grebel, E. K., Gilmore, G., Helmi, A., Kordopatis, G., Lee, Y. S., Munari, U., Navarro, J. F., Parker, Q. A., Quillen, A. C., Reid, W. A., Siebert, A., Siviero, A., Seabroke, G., Watson, F., Williams, M., Minchev, I., Chiappini, C., Martig, M., Steinmetz, M., de Jong, R. S., Boeche, C., Scannapieco, C., Zwitter, T., Wyse, R. F. G., Binney, J. J., Bland-Hawthorn, J., Bienaymé, O., Famaey, B., Freeman, K. C., Gibson, Bradley Kenneth, Grebel, E. K., Gilmore, G., Helmi, A., Kordopatis, G., Lee, Y. S., Munari, U., Navarro, J. F., Parker, Q. A., Quillen, A. C., Reid, W. A., Siebert, A., Siviero, A., Seabroke, G., Watson, F., and Williams, M.

Abstract

The velocity dispersions of stars near the Sun are known to increase with stellar age, but age can be difficult to determine, so a proxy like the abundance of alpha elements (e. g., Mg) with respect to iron, [alpha/Fe], is used. Here we report an unexpected behavior found in the velocity dispersion of a sample of giant stars from the Radial Velocity Experiment survey with high-quality chemical and kinematic information, in that it decreases strongly for stars with [Mg/Fe] > 0.4 dex (i.e., those that formed in the first gigayear of the Galaxy's life). These findings can be explained by perturbations from massive mergers in the early universe, which have affected the outer parts of the disk more strongly, and the subsequent radial migration of stars with cooler kinematics from the inner disk. Similar reversed trends in velocity dispersion are also found for different metallicity subpopulations. Our results suggest that the Milky Way disk merger history can be recovered by relating the observed chemo-kinematic relations to the properties of past merger events.

Published
2014

6. The Sixth Data Release of the Radial Velocity Experiment (R ave). II. Stellar Atmospheric Parameters, Chemical Abundances, and Distances

Author

Savita Mathur, Quentin A. Parker, Diego Bossini, I. Carrillo, Amina Helmi, Cristina Chiappini, Luca Casagrande, Marica Valentini, Paul J. McMillan, Teresa Antoja, Brad K. Gibson, Sanjib Sharma, Kenneth C. Freeman, Benoit Famaey, Andrea Miglio, Harry Enke, Joss Bland-Hawthorn, Rosemary F. G. Wyse, G. R. Ruchti, Georges Kordopatis, George M. Seabroke, Benoit Mosser, Gal Matijevic, Julio F. Navarro, M. Stupar, Fred Watson, Alessandro Siviero, Mary E K Williams, J. P. Fulbright, Gerard Gilmore, Kseniia Sysoliatina, Giacomo Monari, Tomaž Zwitter, Paul Cass, Danijela Birko, Friedrich Anders, Yvonne Elsworth, Eva K. Grebel, Warren A. Reid, Ulisse Munari, Kristin Fiegert, Olivier Bienaymé, Andreas Ritter, Alejandra Recio-Blanco, James Binney, Thaíse S. Rodrigues, Guillaume Guiglion, Arnaud Siebert, Ralf-Dieter Scholz, Patrick de Laverny, Paula Jofre, Andreas Just, D. Burton, Ortwin Gerhard, Jennifer Wojno, Ivan Minchev, William J. Chaplin, Albert Bijaoui, Andrea Kunder, Borja Anguiano, Rafael A. García, Matthias Steinmetz, Leibniz Institute for Astrophysics Potsdam, Australian Astronomical Observatory, Australian National University, Australian Research Council, Agence Nationale de la Recherche (France), German Research Foundation, European Research Council, Istituto Nazionale di Astrofisica, Johns Hopkins University, National Science Foundation (US), W. M. Keck Foundation, Macquarie University, Netherlands Research School for Astronomy, Natural Sciences and Engineering Research Council of Canada, Slovenian Research Agency, Swiss National Science Foundation, Science and Technology Facilities Council (UK), Opticon, Observatoire Astronomique de Strasbourg, University of Basel, University of Groningen, University of Heidelberg, University of Sydney, Centre National D'Etudes Spatiales (France), Ministerio de Economía y Competitividad (España), Kavli Institute for Theoretical Physics, Simons Foundation, Steinmetz M., Guiglion G., McMillan P.J., Matijevic G., Enke H., Kordopatis G., Zwitter T., Valentini M., Chiappini C., Casagrande L., Wojno J., Anguiano B., Bienayme O., Bijaoui A., Binney J., Burton D., Cass P., De Laverny P., Fiegert K., Freeman K., Fulbright J.P., Gibson B.K., Gilmore G., Grebel E.K., Helmi A., Kunder A., Munari U., Navarro J.F., Parker Q., Ruchti G.R., Recio-Blanco A., Reid W., Seabroke G.M., Siviero A., Siebert A., Stupar M., Watson F., Williams M.E.K., Wyse R.F.G., Anders F., Antoja T., Birko D., Bland-Hawthorn J., Bossini D., Garcia R.A., Carrillo I., Chaplin W.J., Elsworth Y., Famaey B., Gerhard O., Jofre P., Just A., Mathur S., Miglio A., Minchev I., Monari G., Mosser B., Ritter A., Rodrigues T.S., Scholz R.-D., Sharma S., Sysoliatina K., Joseph Louis LAGRANGE (LAGRANGE), Université Côte d'Azur (UCA)-Université Nice Sophia Antipolis (... - 2019) (UNS), COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Observatoire de la Côte d'Azur, COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Université Côte d'Azur (UCA)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Observatoire astronomique de Strasbourg (ObAS), Université de Strasbourg (UNISTRA)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), and Astronomy

Subjects
010504 meteorology & atmospheric sciences, ACCURACY, FOS: Physical sciences, Library science, Astrophysics::Cosmology and Extragalactic Astrophysics, 01 natural sciences, surveys, Observatory, 0103 physical sciences, Astrophysics::Solar and Stellar Astrophysics, KINEMATICS, Abundances, 010303 astronomy & astrophysics, Solar and Stellar Astrophysics (astro-ph.SR), Astrophysics::Galaxy Astrophysics, 0105 earth and related environmental sciences, Physics, F-DWARF, European research, Surveys - Stars, Astronomy and Astrophysics, DISC, Astrophysics - Astrophysics of Galaxies, Distances, Astrophysics - Solar and Stellar Astrophysics, stars: abundances - distances, 13. Climate action, Space and Planetary Science, Research council, Astrophysics of Galaxies (astro-ph.GA), PATTERN SPEED, MILKY, Christian ministry, [SDU.ASTR.GA]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Galactic Astrophysics [astro-ph.GA], Astrophysics::Earth and Planetary Astrophysics, EXPERIMENT RAVE, SKY SURVEY, Data release, STARS, ISOCHRONES
Abstract

We present part 2 of the sixth and final Data Release (DR6) of the Radial Velocity Experiment (Rave), a magnitude-limited spectroscopic survey of Galactic stars randomly selected in Earth's southern hemisphere. The Rave medium-resolution spectra (R ∼ 7500) cover the Ca triplet region (8410-8795 Å) and span the complete time frame from the start of Rave observations on 2003 April 12 to their completion on 2013 April 4. In the second of two publications, we present the data products derived from 518,387 observations of 451,783 unique stars using a suite of advanced reduction pipelines focusing on stellar atmospheric parameters, in particular purely spectroscopically derived stellar atmospheric parameters, and the overall metallicity), enhanced stellar atmospheric parameters inferred via a Bayesian pipeline using Gaia DR2 astrometric priors, and asteroseismically calibrated stellar atmospheric parameters for giant stars based on asteroseismic observations for 699 K2 stars. In addition, we provide abundances of the elements Fe, Al, and Ni, as well as an overall [α/Fe] ratio obtained using a new pipeline based on the GAUGUIN optimization method that is able to deal with variable signal-to-noise ratios. The Rave DR6 catalogs are cross-matched with relevant astrometric and photometric catalogs, and are complemented by orbital parameters and effective temperatures based on the infrared flux method. The data can be accessed via the Rave website (http://rave-survey.org) or the Vizier database., Funding for Rave has been provided by: the Leibniz-Institut f¨ur Astrophysik Potsdam (AIP); the Australian Astronomical Observatory; the Australian National University; the Australian Research Council; the French National Research Agency (Programme National Cosmology et Galaxies (PNCG) of CNRS/INSU with INP and IN2P3, co-funded by CEA and CNES); the German Research Foundation (SPP 1177 and SFB 881); the European Research Council (ERC-StG 240271 Galactica); the Istituto Nazionale di Astrofisica at Padova; The Johns Hopkins University; the National Science Foundation of the USA (AST-0908326); the W. M. Keck foundation; the Macquarie University; the Netherlands Research School for Astronomy; the Natural Sciences and Engineering Research Council of Canada; the Slovenian Research Agency (research core funding no. P1-0188); the Swiss National Science Foundation; the Science & Technology Facilities Council of the UK; Opticon; Strasbourg Observatory; and the Universities of Basel, Groningen, Heidelberg, and Sydney. PJM is supported by grant 2017-03721 from the Swedish Research Council. LC is the recipient of the ARC Future Fellowship FT160100402. RAG acknowledges the support from the PLATO CNES grant. SM would like to acknowledge support from the Spanish Ministry with the Ramon y Cajal fellowship number RYC-2015-17697. MS thanks the Research School of Astronomy & Astrophysics in Canberra for support through a Distinguished Visitor Fellowship. RFGW thanks the Kavli Institute for Theoretical Physics and the Simons Foundation for support as a Simons Distinguished Visiting Scholar. This research was supported in part by the National Science Foundation under Grant No. NSF PHY-1748958 to KITP.

Published
2020

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