• A comparative analysis of the observed white dwarf cooling sequence from globular clusters 

      Campos, Fabíola; Bergeron, Pierre; Romero, Alejandra Daniela; Kepler, Souza Oliveira; Ourique, Gustavo; Costa, Jose Eduardo da Silveira; Bonatto, Charles Jose; Winget, Donald Earl; Montgomery, Michael Houston; Pacheco, Thayse Adineia; Bedin, Luigi R. (2016) [Artigo de periódico]
      We report our study of features at the observed red end of the white dwarf cooling sequences for three Galactic globular clusters: NGC 6397, 47 Tucanae and M 4. We use deep colour– magnitude diagrams constructed from ...
    • Evidence of spectral evolution on the white dwarf sample from the Gaia mission 

      Ourique, Gustavo; Kepler, Souza Oliveira; Romero, Alejandra Daniela; Klippel, Theylor Schumacher; Koester, Detlev (2020) [Artigo de periódico]
      Since the Gaia data release 2, several works have been published describing a bifurcation in the observed white dwarf colour−magnitude diagram for GBP−GRP>0. Some possible explanations in the literature include the existence ...
    • Ground-based observation of ZZ Ceti stars and the discovery of four new variables 

      Romero, Alejandra Daniela; Amaral, Larissa Antunes; Klippel, Theylor Schumacher; Sanmartim, David; Fraga, Luciano; Ourique, Gustavo; Pelisoli, Ingrid Domingos; Ramos, Gabriel Lauffer; Kepler, Souza Oliveira; Koester, Detlev (2019) [Artigo de periódico]
      We perform ground-based photometric observations of 22 DA white dwarf stars, 10 already known ZZ Cetis and 12 candidates with atmospheric parameters inside the classical instability strip. We report on the discovery of ...
    • New white dwarf and subdwarf stars in the Sloan Digital Sky Survey Data Release 12 

      Kepler, Souza Oliveira; Pelisoli, Ingrid Domingos; Koester, Detlev; Ourique, Gustavo; Romero, Alejandra Daniela; Reindl, Nicole; Kleinman, Scot James; Eisenstein, Daniel, J.; Valois, Adeilton Dean Marques; Amaral, Larissa Antunes (2016) [Artigo de periódico]
      We report the discovery of 6576 new spectroscopically confirmed white dwarf and subdwarf stars in the Sloan Digital Sky Survey Data Release 12. We obtain Teff, log g and mass for hydrogen atmospherewhite dwarf stars (DAs) ...
    • New white dwarf stars in the Sloan Digital Sky Survey Data Release 10 

      Kepler, Souza Oliveira; Pelisoli, Ingrid Domingos; Koester, Detlev; Ourique, Gustavo; Kleinman, Scot James; Romero, Alejandra Daniela; Nitta, Atsuko; Eisenstein, Daniel, J.; Costa, Jose Eduardo da Silveira; Kulebi, Baybars; Jordan, Stefan; Dufour, Patrick; Giommi, Paolo; Rebassa-Mansergas, Alberto (2015) [Artigo de periódico]
      We report the discovery of 9088 new spectroscopically confirmed white dwarfs and subdwarfs in the Sloan Digital Sky Survey Data Release 10. We obtain Teff, log g and mass for hydrogen atmosphere white dwarf stars (DAs) and ...
    • A study of cool white dwarfs in the Sloan Digital Sky Survey Data Release 12 

      Ourique, Gustavo; Romero, Alejandra Daniela; Kepler, Souza Oliveira; Koester, Detlev; Amaral, Larissa Antunes (2019) [Artigo de periódico]
      In this work, we study white dwarfs where 30 000K > Teff > 5000K to compare the differences in the cooling of DAs and non-DAs and their formation channels. Our final sample is composed by nearly 13 000 DAs and more than 3 ...
    • White dwarf and subdwarf stars in the Sloan Digital Sky Survey Data Release 14 

      Kepler, Souza Oliveira; Pelisoli, Ingrid Domingos; Koester, Detlev; Reindl, Nicole; Geier, Stephan; Romero, Alejandra Daniela; Ourique, Gustavo; Oliveira, Cristiane de Paula; Amaral, Larissa Antunes (2019) [Artigo de periódico]
      White dwarfs carry information on the structure and evolution of the Galaxy, especially through their luminosity function and initial-to-final mass relation. Very cool white dwarfs provide insight into the early ages of ...
    • White dwarf and subdwarf stars in the Sloan Digital Sky Survey Data Release 16 

      Kepler, Souza Oliveira; Koester, Detlev; Pelisoli, Ingrid Domingos; Romero, Alejandra Daniela; Ourique, Gustavo (2021) [Artigo de periódico]
      White dwarfs are the end state of the evolution of more than 97 per cent of all stars, and therefore carry information on the structure and evolution of the Galaxy through their luminosity function and initial-to-final ...