• 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 survey of early-type stars based on the Two Micron All Sky Survey database 

      Ortiz, Roberto Pereira; Malacarne, Marcio; Wilhelm, Ronald; Costa, R. D. D.; Rossi, Silvia; Maciel, Walter Junqueira (2007) [Artigo de periódico]
      We report the results of a spectroscopic survey of blue stars near the south Galactic pole, selected according to their color indices in the 2MASS database. The main scope of this work is to determine the nature of the ...
    • The McDonald Observatory search for pulsating sdA stars : asteroseismic support for multiple populations 

      Bell, Keaton; Pelisoli, Ingrid Domingos; Kepler, Souza Oliveira; Brown, Warren R.; Winget, Donald Earl; Winget, K. I.; Vanderbosch, Zachary; Castanheira, Bárbara Garcia; Hermes, James J.; Montgomery, Michael Houston; Koester, Detlev (2018) [Artigo de periódico]
      Context. The nature of the recently identified “sdA” spectroscopic class of stars is not well understood. The thousands of known sdAs have H-dominated spectra, spectroscopic surface gravity values between main sequence ...
    • The sdA problem : III. New extremely low-mass white dwarfs and their precursors from Gaia astrometry 

      Pelisoli, Ingrid Domingos; Bell, Keaton; Kepler, Souza Oliveira; Koester, Detlev (2019) [Artigo de periódico]
      The physical nature of the sdA stars – cool hydrogen-rich objects with spectroscopic surface gravities intermediate between main-sequence and canonical-mass white dwarfs – has been elusive since they were found in Sloan ...
    • The sdA problem : II. Photometric and spectroscopic follow-up 

      Pelisoli, Ingrid Domingos; Kepler, Souza Oliveira; Koester, Detlev; Castanheira, Bárbara Garcia; Romero, Alejandra Daniela; Fraga, Luciano (2018) [Artigo de periódico]
      The spectral classification ‘subdwarfA’ (sdA) is given to stars showingH-rich spectra and submain- sequence surface gravities, but effective temperature lower than the zero-age horizontal branch. Their evolutionary origin ...
    • The sdA problem : I. Physical properties 

      Pelisoli, Ingrid Domingos; Kepler, Souza Oliveira; Koester, Detlev (2018) [Artigo de periódico]
      The so-called sdA stars are defined by having H-rich spectra and surface gravities similar to hot subdwarf stars, but effective temperature below the zero-age horizontal branch. Their evolutionary history is an enigma: ...
    • White dwarf and subdwarf stars in the sloan digital sky survey 

      Pelisoli, Ingrid Domingos (2018) [Tese]
      White dwarf stars are the final observable evolutionary state of over 95% of stars and also a common outcome in binary evolution. Therefore, studying white dwarfs is a powerful tool to understand both single and binary ...
    • 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 ...
    • Whole Earth Telescope observations of the pulsating subdwarf B star PG 0014+067 

      Vuckovic, Maja; Kawaler, Steven D.; O'Toole, Simon; Csubry, Z.; Baran, Andrzej; Zola, Staszek; Moskalik, Pawel; Klumpe, Eric W.; Riddle, Reed L.; O'Brien, M. Sean; Mullally, Fergal; Wood, Matthew A.; Wilkat, Vanessa; Zhou, Ai-Ying; Reed, M. D.; Terndrup, Donald M.; Sullivan, Denis J.; Kim, Seung-Lee; Chen, Wen-Ping; Chen, C.-W.; Hsiao, Wen-Shan; Kausharbanu, Sanchawala; Lee, Hsu-Tai; Jiang, Xiaojun; Janulis, Rimvydas; Siwak, Michal; Ogloza, Waldemar; Paparo, Margit; Bognár, Zsófia; Sódor, Ádám; Handler, Gerald; Lorenz, Denise; Steininger, Bruno; Silvotti, Roberto; Vauclair, Gérard; Oreiro, Raquel; Ostensen, Roy; Bronowska, A.; Castanheira, Bárbara Garcia; Kepler, Souza Oliveira; Fraga, Luciano; Shipman, Harry L.; Provencal, Judith L.; Childers, D. (2006) [Artigo de periódico]
      PG 0014+067 is one of the most promising pulsating subdwarf B stars for seismic analysis, as it has a rich pulsation spectrum. The richness of its pulsations, however, poses a fundamental challenge to understanding the ...
    • Whole Earth Telescope observations of the subdwarf B star KPD1930+2752 : a rich, short-period pulsator in a close binary 

      Reed, M. D.; Harms, S. L.; Poindexter, S.; Zhou, Ai-Ying; Eggen, J.; Morris, M. A.; Quint, A. C.; McDaniel, S.; Baran, Andrzej; Dolez, Noël; Kawaler, Steven D.; Kurtz, Donald W.; Moskalik, Pawel; Riddle, Reed L.; Zola, Staszek; Ostensen, Roy; Solheim, Jan-Eric; Kepler, Souza Oliveira; Costa, Alex Fabiano Murillo da; Provencal, Judith L.; Mullally, Fergal; Winget, Donald Earl; Vuckovic, Maja; Crowe, Richard A.; Terry, D.; Avila, R.; Berkey, B.; Stewart, S.; Bodnarik, J.; Bolton, D.; Binder, Philippe M.; Sekiguchi, Kazuhiro; Sullivan, Denis J.; Kim, Seung-Lee; Chen, Wen-Ping; Chen, C.-W.; Lin, Hung-Chin; Jiang, Xiaojun; Wu, H.; Gou, J.-P.; Liu, Z.; Leibowitz, Elia M.; Lipkin, Y.; Akan, Mustafa Can; Cakirli, Ö; Janulis, Rimvydas; Pretorius, R.; Ogloza, Waldemar; Stachowski, G.; Paparo, Margit; Szabó, R.; Csubry, Z.; Zsuffa, D.; Silvotti, Roberto; Marinoni, S.; Bruni, I.; Vauclair, Gérard; Chevreton, Michel; Matthews, Jaymie M.; Cameron, C.; Pablo, H. (2011) [Artigo de periódico]
      KPD 1930+2752 is a short-period pulsating subdwarf B (sdB) star. It is also an ellipsoidal variable with a known binary period of 2.3 h. The companion is most likely a white dwarf and the total mass of the system is close ...