• 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 ...
    • 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 ...
    • Delta Scuti Network observations of XX Pyx : detection of 22 pulsation modes and of short-term amplitude and frequency variations 

      Handler, Gerald; Arentoft, T.; Shobbrook, Robert R.; Wood, Matthew A.; Crause, L.A.; Crake, P.; Podmore, F.; Habanyama, A.; Oswalt, T.; Birch, P.; Lowe, G.; Sterken, C.; Meintjes, P.; Brink, J.; Claver, C.F.; Medupe, R.; Guzik, Joyce Ann; Beach, T.E.; Martinez, Peter; Leibowitz, Elia M.; Ibbetson, Peter A.; Smith, T.; Ashoka, B.N.; Raj, N.E.; Kurtz, Donald W.; Balona, L.A.; O'Donoghue, Darragh; Costa, Jose Eduardo da Silveira; Breger, M. (2000) [Artigo de periódico]
      We report multisite observations devoted to the main-sequence δ Scuti star XX Pyx, conducted as the 17th run of the Delta Scuti Network. Over 125 nights a total of 550 h of usable time-series photometric B- and V-filter ...
    • 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 pulsations of PG 1351+489 

      Redaelli, Maurício; Kepler, Souza Oliveira; Costa, Jose Eduardo da Silveira; Winget, Donald Earl; Handler, Gerald; Castanheira, Bárbara Garcia; Kanaan Neto, Antonio Nemer; Fraga, Luciano; Henrique, P.; Giovannini Junior, Odilon; Provencal, Judith L.; Shipman, Harry L.; Dalessio, J.; Thompson, S. E.; Mullally, Fergal; Brewer, M. M.; Childers, D.; Oksala, M. E.; Rosen, Rachel; Wood, Matthew A.; Reed, M. D.; Walter, B.; Strickland, Willie; Chandler, Dean W.; Watson, Todd K.; Nather, R. Edward; Montgomery, Michael Houston; Bischoff-Kim, Agnès; Hansen, Carl J.; Nitta, Atsuko; Kleinman, Scot James; Claver, C.F.; Brown, Tim; Sullivan, Denis J.; Kim, Seung-Lee; Chen, Wen-Ping; Yang, M.; Shih, Chia-You; Zhang, X; Jiang, Xiaojun; Fu, Jianning Ning; Seetha, S.; Ashoka, B.N.; Marar, T.M. Krishnan; Baliyan, Kiran S.; Vats, Hari Om; Chernyshev, A.V.; Ibbetson, Peter A.; Leibowitz, Elia M.; Hemar, Shirley; Sergeev, A.; Andreev, M.; Janulis, Rimvydas; Meistas, Edmundas G.; Moskalik, Pawel; Pajdosz, Gabriel; Baran, Andrzej; Winiarski, M.; Zola, Staszek; Ogloza, Waldemar; Siwak, Michal; Bognár, Zsófia; Solheim, Jan-Eric; Sefako, R.; Buckley, David A.H.; O'Donoghue, Darragh; Nagel, Thorsten; Silvotti, Roberto; Bruni, I.; Fremy, J. R.; Vauclair, Gérard; Chevreton, Michel; Dolez, Noël; Pfeiffer, Ben; Barstow, Martin A.; Creevey, o; Kawaler, Steven D.; Clemens, J. Christopher (2011) [Artigo de periódico]
      PG 1351+489 is one of the 20DBVs – pulsating helium-atmospherewhite dwarf stars – known and has the simplest power spectrum for this class of star, making it a good candidate to study cooling rates. We report accurate ...
    • A Whole Earth Telescope campaign on the pulsating subdwarf B binary system PG 1336-018 (NY Vir) 

      Kilkenny, Dave; Reed, M. D.; O'Donoghue, Darragh; Kawaler, Steven D.; Mukadam, Anjum Shagufta; Kleinman, Scot James; Nitta, Atsuko; Metcalfe, Travis S.; Provencal, Judith L.; Watson, Todd K.; Sullivan, Denis J.; Sullivan, Terry; Shobbrook, Robert R.; Jiang, Xiaojun; Joshi, Santosh; Ashoka, B.N.; Seetha, S.; Leibowitz, Elia M.; Ibbetson, Peter A.; Mendelson, Haim; Meistas, Edmundas G.; Kalytis, Romualdas; Alisauskas, Darius; Martinez, Peter; Van Wyk, Francois; Stobie, Robert S.; Marang, Fred; Zola, Staszek; Krzesinski, Jerzy; Ogloza, Waldemar; Moskalik, Pawel; Silvotti, Roberto; Piccioni, Adalberto; Vauclair, Gérard; Dolez, Noël; Chevreton, Michel; Dreizler, Stefan; Schuh, Sonja L.; Deetjen, Jochen L.; Solheim, Jan-Eric; Gonzalez Perez, Jose Miguel; Ulla, Ana; Ostensen, Roy; Manteiga, Minia; Suarez, Olga; Burleigh, Matt; Kepler, Souza Oliveira; Kanaan Neto, Antonio Nemer; Giovannini Junior, Odilon (2003) [Artigo de periódico]
      We present results from a multisite (‘Whole Earth Telescope’) photometric campaign on PG 1336−018, the close eclipsing binary system containing a pulsating subdwarf B (sdB) star. The main part of the campaign (1999 April) ...
    • 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 ...