• Asteroseismology of a star cooled by neutrino emission : the pulsating pre-white dwarf PG 0122+200 

      O'Brien, M. Sean; Vauclair, Gérard; Kawaler, Steven D.; Watson, Todd K.; Winget, Donald Earl; Nather, R. Edward; Montgomery, Michael Houston; Nitta, Atsuko; Kleinman, Scot James; Sullivan, Denis J.; Jiang, Xiaojun; Marar, T.M. Krishnan; Seetha, S.; Ashoka, B.N.; Bhattacharya, J.; Leibowitz, Elia M.; Hemar, Shirley; Ibbetson, Peter A.; Warner, B.; Van Zyl, L.; Moskalik, Pawel; Zola, Staszek; Pajdosz, Gabriel; Krzesinski, Jerzy; Dolez, Noël; Chevreton, Michel; Solheim, Jan-Eric; Thomassen, T.; Kepler, Souza Oliveira; Giovannini Junior, Odilon; Provencal, Judith L.; Wood, Matthew A.; Clemens, J. Christopher (1998) [Artigo de periódico]
      Observation of g-mode pulsations in the variable pre-white dwarf (GW Virginis) stars provides a unique means to probe their interiors and to study the late stages of stellar evolution. Multisite campaigns have in several ...
    • Asteroseismology of RXJ 2117+3412, the hottest pulsating PG 1159 star 

      Vauclair, Gérard; Moskalik, Pawel; Pfeiffer, Ben; Chevreton, Michel; Dolez, Noël; Serre, B.; Kleinman, Scot James; Barstow, Martin A.; Sansom, A.E.; Solheim, Jan-Eric; Belmonte, J.A.; Kawaler, Steven D.; Kepler, Souza Oliveira; Kanaan Neto, Antonio Nemer; Giovannini Junior, Odilon; Winget, Donald Earl; Watson, Todd K.; Nather, R. Edward; Clemens, J. Christopher; Provencal, Judith L.; Dixson, James S.; Yanagida, K.; Nitta, Atsuko; Montgomery, Michael Houston; Klumpe, Eric W.; Bruvold, A.; O'Brien, M. Sean; Hansen, Carl J.; Grauer, Albert D.; Bradley, Paul A.; Wood, Matthew A.; Achilleos, Nicholas; Jiang, Shi Yang; Fu, Jianning Ning; Marar, T.M. Krishnan; Ashoka, B.N.; Meistas, Edmundas G.; Chernyshev, A.V.; Mazeh, Tsevi; Leibowitz, Elia M.; Hemar, Shirley; Krzesinski, Jerzy; Pajdosz, Gabriel; Zola, Staszek (2002) [Artigo de periódico]
      The pulsating PG 1159 planetary nebula central star RXJ 2117+3412 has been observed over three successive seasons of a multisite photometric campaign. The asteroseismological analysis of the data, based on the 37 identified ...
    • Constraining the evolution of ZZ Ceti 

      Mukadam, Anjum Shagufta; Kepler, Souza Oliveira; Winget, Donald Earl; Nather, R. Edward; Kilic, Mukremin; Mullally, Fergal; Von Hippel, Theodore A.; Kleinman, Scot James; Nitta, Atsuko; Guzik, Joyce Ann; Bradley, Paul A.; Matthews, Jaymie M.; Sekiguchi, Kazuhiro; Sullivan, Denis J.; Sullivan, Terry; Shobbrook, Robert R.; Birch, P.; Jiang, Xiaojun; Xu, D.W.; Joshi, Santosh; Ashoka, B.N.; Ibbetson, Peter A.; Leibowitz, Elia M.; Ofek, Eran O.; Meistas, Edmundas G.; Janulis, Rimvydas; Alisauskas, Darius; Kalytis, Romualdas; Handler, Gerald; Kilkenny, Dave; O'Donoghue, Darragh; Kurtz, Donald W.; Muller, M.; Moskalik, Pawel; Ogloza, Waldemar; Zola, Staszek; Krzesinski, Jerzy; Johannessen, F.; Gonzalez Perez, Jose Miguel; Solheim, Jan-Eric; Silvotti, Roberto; Bernabei, S.; Vauclair, Gérard; Dolez, Noël; Fu, Jianning Ning; Chevreton, Michel; Manteiga, Minia; Suarez, Olga; Ulla, Ana; Cunha, Margarida S.; Metcalfe, Travis S.; Kanaan Neto, Antonio Nemer; Fraga, Luciano; Costa, Alex Fabiano Murillo da; Giovannini Junior, Odilon; Fontaine, Gilles; Bergeron, Pierre; O'Brien, M. Sean; Sanwal, Divas; Wood, Matthew A.; Ahrens, T.J.; Silvestri, Nicole M.; Klumpe, Eric W.; Kawaler, Steven D.; Riddle, Reed L.; Reed, M. D.; Watson, Todd K. (2003) [Artigo de periódico]
      We report our analysis of the stability of pulsation periods in the DAV star (pulsating hydrogen atmosphere white dwarf ) ZZ Ceti, also called R548. On the basis of observations that span 31 years, we conclude that the ...
    • New whole earth telescope observations of cd-247599 : steps towards delta scuti star seismology 

      Handler, Gerald; Pikall, H.; O'Donoghue, Darragh; Buckley, David A.H.; Vauclair, Gérard; Chevreton, Michel; Giovannini Junior, Odilon; Kepler, Souza Oliveira; Goode, P.R.; Provencal, Judith L.; Wood, Matthew A.; Clemens, J. Christopher; O'Brien, M. Sean; Nather, R. Edward; Winget, Donald Earl; Kleinman, Scot James; Kanaan Neto, Antonio Nemer; Watson, Todd K.; Nitta, Atsuko; Montgomery, Michael Houston; Klumpe, Eric W.; Bradley, Paul A.; Sullivan, Denis J.; Wu, K.; Marar, T.M. Krishnan; Seetha, S.; Ashoka, B.N.; Mahra, H.S.; Bhat, B.C.; Babu, V.C.; Leibowitz, Elia M.; Hemar, Shirley; Ibbetson, Peter A.; Mashal, E.; Meistas, Edmundas G.; Dziembowski, W.A.; Pamyantnykh, A.A.; Moskalik, Pawel; Zola, Staszek; Pajdosz, Gabriel; Krzesinski, Jerzy; Solheim, Jan-Eric; Bard, S.; Massarand, C.M.; Breger, M.; Gelbmann, M.J.; Paunzen, E.; North, P. (1997) [Artigo de periódico]
      92 h of new Whole Earth Telescope observations have been acquired for the δ Scuti star CD -24 7599. All the seven pulsation modes reported by Handler et al. are confirmed. However, significant amplitude variations which ...
    • Normal modes and discovery of high-order cross-frequencies in the DBV white dwarf GD 358 

      Vuille, F.; O'Donoghue, Darragh; Buckley, David A.H.; Massacand, C.N.; Solheim, Jan-Eric; Bard, S.; Vauclair, Gérard; Giovannini Junior, Odilon; Kepler, Souza Oliveira; Kanaan Neto, Antonio Nemer; Provencal, Judith L.; Wood, Matthew A.; Clemens, J. Christopher; Kleinman, Scot James; O'Brien, M. Sean; Nather, R. Edward; Winget, Donald Earl; Nitta, Atsuko; Klumpe, Eric W.; Montgomery, Michael Houston; Watson, Todd K.; Bradley, Paul A.; Sullivan, Denis J.; Wu, K.; Marar, T.M. Krishnan; Seetha, S.; Ashoka, B.N.; Mahra, H.S.; Bhat, B.C.; Babu, V.C.; Leibowitz, Elia M.; Hemar, Shirley; Ibbetson, Peter A.; Mashal, E.; Meistas, Edmundas G.; Moskalik, Pawel; Zola, Staszek; Krzesinski, Jerzy; Pajdosz, Gabriel (2000) [Artigo de periódico]
      We present a detailed mode identification performed on the 1994 Whole Earth Telescope (WET) run on GD 358. The results are compared with that obtained for the same star from the 1990 WET data. The two temporal spectra show ...
    • The pulsation modes of the pre-white dwarf PG 1159-035 

      Costa, Jose Eduardo da Silveira; Kepler, Souza Oliveira; Winget, Donald Earl; O'Brien, M. Sean; Kawaler, Steven D.; Costa, Alex Fabiano Murillo da; Giovannini Junior, Odilon; Kanaan Neto, Antonio Nemer; Mukadam, Anjum Shagufta; Mullally, Fergal; Nitta, Atsuko; Provencal, Judith L.; Shipman, Harry L.; Wood, Matthew A.; Ahrens, T.J.; Grauer, Albert D.; Kilic, Mukremin; Bradley, Paul A.; Sekiguchi, Kazuhiro; Crowe, Richard A.; Jiang, Xiaojun; Sullivan, Denis J.; Sullivan, Terry; Rosen, Rachel; Clemens, J. Christopher; Janulis, Rimvydas; O'Donoghue, Darragh; Ogloza, Waldemar; Baran, Andrzej; Silvotti, Roberto; Marinoni, S.; Vauclair, Gérard; Dolez, Noël; Chevreton, Michel; Dreizler, Stefan; Schuh, Sonja L.; Deetjen, Jochen L.; Nagel, Thorsten; Solheim, Jan-Eric; Gonzalez Perez, Jose Miguel; Ulla, Ana; Barstow, Martin A.; Burleigh, Matt; Good, Simon A.; Metcalfe, Travis S.; Kim, Seung-Lee; Lee, H.; Sergeev, A.; Akan, Mustafa Can; Cakirli, Ö; Paparo, Margit; Virághalmy, Géza; Ashoka, B.N.; Handler, Gerald; Hürkal, Özlem; Johannessen, F.; Kleinman, Scot James; Kalytis, Romualdas; Krzesinski, Jerzy; Klumpe, Eric W.; Larrison, Jesse; Lawrence, T.; Meistas, Edmundas G.; Martinez, Peter; Nather, R. Edward; Fu, Jianning Ning; Pakstiene, Erika; Rosen, R.; Romero-Colmenero, Encarni; Riddle, Reed L.; Seetha, S.; Silvestri, Nicole M.; Vuckovic, Maja; Warner, B.; Zola, Staszek; Althaus, Leandro Gabriel; Córsico, Alejandro Hugo; Montgomery, Michael Houston (2008) [Artigo de periódico]
      Context. PG 1159-035, a pre-white dwarf with Teff ~_140 000 K, is the prototype of both two classes: the PG 1159 spectroscopic class and the DOV pulsating class. Previous studies of PG 1159-035 photometric data obtained ...
    • Whole Earth Telescope observations and seismological analysis of the pre-white dwarf pg 2131+066 

      Kawaler, Steven D.; O'Brien, M. Sean; Clemens, J. Christopher; Nather, R. Edward; Winget, Donald Earl; Watson, Todd K.; Yanagida, K.; Dixson, James S.; Bradley, Paul A.; Wood, Matthew A.; Sullivan, Denis J.; Kleinman, Scot James; Meistas, Edmundas G.; Leibowitz, Elia M.; Moskalik, Pawel; Zola, Staszek; Pajdosz, Y.; Krzesinski, Jerzy; Solheim, Jan-Eric; Bruvold, A.; O'Donoghue, Darragh; Katz, M.; Vauclair, Gérard; Dolez, Noël; Chevreton, Michel; Barstow, Martin A.; Kanaan Neto, Antonio Nemer; Kepler, Souza Oliveira; Giovannini Junior, Odilon; Provencal, Judith L.; Hansen, Carl J. (1995) [Artigo de periódico]
      As transition objects between the asymptotic giant branch (AGB) and cooling white dwarfs, the PG 1159 stars are key objects for understanding the late stages of stellar evolution. The pulsations exhibited by many members ...
    • Whole Earth Telescope observations of BPM 37093 : a seismological test of crystallization theory in white dwarfs 

      Kanaan Neto, Antonio Nemer; Nitta, Atsuko; Winget, Donald Earl; Kepler, Souza Oliveira; Montgomery, Michael Houston; Metcalfe, Travis S.; Oliveira, H.; Fraga, Luciano; Costa, Alex Fabiano Murillo da; Costa, Jose Eduardo da Silveira; Castanheira, Bárbara Garcia; Giovannini Junior, Odilon; Nather, R. Edward; Mukadam, Anjum Shagufta; Kawaler, Steven D.; O'Brien, M. Sean; Reed, M. D.; Kleinman, Scot James; Provencal, Judith L.; Watson, Todd K.; Kilkenny, Dave; Sullivan, Denis J.; Sullivan, Terry; Shobbrook, Bob; Jiang, Xiaojun; Ashoka, B.N.; Seetha, S.; Leibowitz, Elia M.; Ibbetson, Peter A.; Mendelson, Haim; Meistas, Edmundas G.; Kalytis, Romualdas; Alisauskas, Darius; O'Donoghue, Darragh; Buckley, David A.H.; Martinez, Peter; Van Wyk, Francois; Stobie, Robert S.; Marang, Fred; Van Zyl, L.; Ogloza, Waldemar; Krzesinski, Jerzy; Zola, Staszek; Moskalik, Pawel; Breger, M.; Stankov, A.; Silvotti, Roberto; Piccioni, Adalberto; Vauclair, Gérard; Dolez, Noël; Chevreton, Michel; Deetjen, Jochen L.; Dreizler, Stefan; Schuh, Sonja L.; Gonzalez Perez, Jose Miguel; Ostensen, Roy; Ulla, Ana; Manteiga, Minia; Suarez, Olga; Burleigh, Matt; Barstow, Martin A. (2005) [Artigo de periódico]
      BPM 37093 is the only hydrogen-atmosphere white dwarf currently known which has sufficient mass (~1.1 Mʘ) to theoretically crystallize while still inside the ZZ Ceti instability strip (Teff ~ 12 000 K). As a consequence, ...
    • Whole Earth Telescope observations of the hot helium atmosphere pulsating white dwarf EC 20058−5234 

      Sullivan, Denis J.; Metcalfe, Travis S.; O'Donoghue, Darragh; Winget, Donald Earl; Kilkenny, Dave; Van Wyk, Francois; Kanaan Neto, Antonio Nemer; Kepler, Souza Oliveira; Nitta, Atsuko; Kawaler, Steven D.; Montgomery, Michael Houston; Nather, R. Edward; O'Brien, M. Sean; Bischoff-Kim, Agnès; Wood, Matthew A.; Jiang, Xiaojun; Leibowitz, Elia M.; Ibbetson, Peter A.; Zola, Staszek; Krzesinski, Jerzy; Pajdosz, Gabriel; Vauclair, Gérard; Dolez, Noël; Chevreton, Michel (2008) [Artigo de periódico]
      We present the analysis of a total of 177 h of high-quality optical time-series photometry of the helium atmosphere pulsating white dwarf (DBV) EC 20058−5234. The bulk of the observations (135 h) were obtained during a WET ...
    • Whole earth telescope observations of the pulsating hot white dwarf PG 1707+427 

      Kawaler, Steven D.; Potter, E. M.; Vuckovic, Maja; O'Toole, Simon; Clemens, J. Christopher; O'Brien, M. Sean; Grauer, Albert D.; Nather, R. Edward; Moskalik, Pawel; Fontaine, Gilles; Wesemael, F.; Bergeron, Pierre; Vauclair, Gérard; Dolez, Noël; Chevreton, Michel; Kleinman, Scot James; Watson, Todd K.; Barstow, Martin A.; Dind, Z. E.; Sansom, A.E.; Winget, Donald Earl; Kepler, Souza Oliveira; Kanaan Neto, Antonio Nemer; Bradley, Paul A.; Dixson, James S.; Provencal, Judith L.; Bedding, T. R. (2004) [Artigo de periódico]
      We report on the analysis of multisite time-series photometry of the pulsating pre-white dwarf (GW Vir star) PG 1707+427, obtained by the Whole Earth Telescope collaboration. This is the last of the known GW Vir stars ...
    • 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 ...