• Abundances from integrated spectra of 47 Tucanae (NGC 104) 

      Rennó, Christiano Santos; Barbuy, Beatriz; Moura, Tatiana; Trevisan, Marina (2020) [Artigo de periódico]
      47 Tucanae is among the most studied and observed globular clusters, given its proximity. The aim of this work is to study in detail the integrated spectrum of 47 Tucanae, as a template, in order to have a list of reliable ...
    • Carbon, isotopic ratio 12C/13C, and nitrogen in solar twins : constraints for the chemical evolution of the local disc 

      Botelho, Rafael Bueno; Milone, André de Castro; Meléndez, Jorge; Alves-Brito, Alan; Spina, Lorenzo; Bean, Jacob L. (2020) [Artigo de periódico]
      Abundances of light elements in dwarf stars of different ages are important constraints for stellar yields, Galactic chemical evolution and exoplanet chemical composition studies. We have measured C and N abundances and ...
    • Chemical abundances in Seyfert galaxies : VII. Direct abundance determination of neon based on optical and infrared emission lines 

      Armah, Mark; Dors Júnior, Oli Luiz; Aydar, Catarina; Cardaci, Mónica V.; Hägelle, Guillermo Federico; Feltre, Anna; Riffel, Rogério; Riffel, Rogemar André; Krabbe, Angela Cristina (2021) [Artigo de periódico]
      For the first time, neon abundance has been derived in the narrow line region from a sample of Seyfert 2 nuclei. In view of this, we compiled from the literature fluxes of optical and infrared (IR) narrow emission lines ...
    • Dissecting stellar chemical abundance space with t-SNE 

      Anders, Friedrich; Chiappini, C.C.M.; Santiago, Basilio Xavier; Matijeviĉ, Gal; Queiroz, Anna Bárbara de Andrade; Steinmetz, M.; Guiglion, Guillaume (2018) [Artigo de periódico]
      In the era of large-scale Galactic astronomy and multi-object spectroscopic stellar surveys, the sample sizes and the number of available stellar chemical abundances have reached dimensions in which it has become difficult ...
    • High-resolution abundance analysis of four red giants in the globular cluster NGC 6558 

      Barbuy, Beatriz; Muniz, Leone V.; Ortolani, Sergio; Ernandes, Heitor; Dias, Bruno Moreira de Souza; Saviane, Ivo; Kerber, Leandro de Oliveira; Bica, Eduardo Luiz Damiani; Pérez Villegas, Maria de Los Angeles; Rossi, Luca James; Held, Enrico V. (2018) [Artigo de periódico]
      Context. NGC 6558 is a bulge globular cluster with a blue horizontal branch (BHB), combined with a metallicity of [Fe/H] ≈ −1.0. It is similar to HP 1 and NGC 6522, which could be among the oldest objects in the Galaxy. ...
    • SDSS-IV MaNGA : exploring the local scaling relations for N/O 

      Schaefer, Adam L.; Tremonti, Christy A.; Kauffmann, Guinevere; Andrews, Brett H.; Bershady, Matthew A.; Boardman, Nicholas Fraser; Bundy, Kevin; Drory, Niv; Fernández-Trincado, José Gregorio; Preece, Holly; Riffel, Rogério; Riffel, Rogemar André; Sánchez, Sebastián F. (2022) [Artigo de periódico]
      We present, for the first time, the relationship between local stellar mass surface density, Σ*, and N/O derived from SDSS-IV MaNGA data, using a sample of 792,765 high signal-to-noise ratio star-forming spaxels. Using a ...
    • StarHorse results for spectroscopic surveys and Gaia DR3 : chrono-chemical populations in the solar vicinity, the genuine thick disk, and young alpha-rich stars 

      Queiroz, Anna Bárbara de Andrade; Anders, Friedrich; Chiappini, C.C.M.; Barbuy, Beatriz; Khalatyan, Arman V.; Santiago, Basilio Xavier; Nepal, Samir; Steinmetz, M.; Gallart, Carme; Valentini, Marica; Dal Ponte, Marina; Barbuy, Beatriz; Pérez Villegas, Maria de Los Angeles; Masseron, Thomas; Fernández-Trincado, José Gregorio; Khoperskov, Sergey A.; Minchev, Ivan; Fernández Alvar, Emma; Lane, Richard R.; Nitschelm, Christian (2023) [Artigo de periódico]
      The Gaia mission has provided an invaluable wealth of astrometric data for more than a billion stars in our Galaxy. The synergy between Gaia astrometry, photometry, and spectroscopic surveys gives us comprehensive information ...
    • The 16th data release of the sloan digital sky surveys : first release from the APOGEE-2 Southern Survey and full release of eBOSS spectra 

      Ahumada, Romina; Riffel, Rogério; Storchi-Bergmann, Thaisa; Zou, Hu (2020) [Artigo de periódico]
      Twenty years have passed since first light for the Sloan Digital Sky Survey (SDSS). Here, we release data taken by the fourth phase of SDSS (SDSS-IV) across its first three years of operation (2014 July–2017 July). This ...
    • The impact of the uncertainties in the 12C(α, γ ) 16O reaction rate on the evolution of low- to intermediate-mass stars 

      Pepper, Ben Thomas; Istrate, Alina G.; Romero, Alejandra Daniela; Kepler, Souza Oliveira (2022) [Artigo de periódico]
      One of the largest uncertainties in stellar evolutionary computations is the accuracy of the considered reaction rates. The 12C(α, γ ) 16O reaction is particularly important for the study of low- and intermediate-mass stars ...