• 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 ...
    • Discovery of eleven new ZZ Ceti stars 

      Reimers, Dieter; Castanheira, Bárbara Garcia; Kepler, Souza Oliveira; Mullally, Fergal; Winget, Donald Earl; Koester, Detlev; Voss, Björn; Kleinman, Scot James; Nitta, Atsuko; Eisenstein, D.J.; Napiwotzki, Ralf (2006) [Artigo de periódico]
      We report the discovery of eleven new ZZ Cetis using telescopes at OPD (Observatório do Pico dos Dias/LNA) in Brazil, the 4.1 m SOAR (Southern Astrophysical Research) telescope at Cerro Pachon, Chile, and the 2.1 m Otto ...
    • Discovery of fourteen new ZZ Cetis with SOAR 

      Kepler, Souza Oliveira; Castanheira, Bárbara Garcia; Saraiva, Maria de Fátima Oliveira; Nitta, Atsuko; Kleinman, Scot James; Mullally, Fergal; Winget, Donald Earl; Eisenstein, D.J. (2005) [Artigo de periódico]
      We report the discovery of fourteen new ZZ Cetis with the 4.1 m Southern Astrophysical Research telescope, at Cerro Pachon, in Chile. The candidates were selected from the SDSS (Sloan Digital Sky Survey) DA white dwarf ...
    • Eleven new DA white dwarf variable stars from the Sloan Digital Sky Survey 

      Mullally, Fergal; Thompson, S. E.; Castanheira, Bárbara Garcia; Winget, Donald Earl; Kepler, Souza Oliveira; Eisenstein, D.J.; Kleinman, Scot James; Nitta, Atsuko (2005) [Artigo de periódico]
      We report the discovery of 11 new variable DAwhite dwarf (ZZ Ceti) stars. Candidates were selected by deriving temperatures from model fits to spectra obtained from the Sloan Digital Sky Survey (SDSS). We also find objects ...
    • Limits on planets around pulsating white dwarf stars 

      Mullally, Fergal; Winget, Donald Earl; DeGennaro, Steven; Jeffery, Elizabeth; Thompson, S. E.; Chandler, Dean W.; Kepler, Souza Oliveira (2008) [Artigo de periódico]
      We present limits on planetary companions to pulsating white dwarf stars. A subset of these stars exhibit extreme stability in the period and phase of some of their pulsation modes; a planet can be detected around such a ...
    • Measuring the evolutionay rate of cooling of ZZ Ceti 

      Mukadam, Anjum Shagufta; Bischoff-Kim, Agnès; Fraser, Oliver; Córsico, Alejandro Hugo; Montgomery, Michael Houston; Kepler, Souza Oliveira; Romero, Alejandra Daniela; Kronberg, M. E.; Winget, K. I.; Falcon, Ross E.; Chandler, Dean W.; Kuehne, J. W.; Sullivan, Denis J.; Reaves, David Earl; Von Hippel, Theodore A.; Mullally, Fergal; Shipman, Harry L.; Thompson, S. E.; Silvestri, Nicole M.; Hynes, R. I. (2013) [Artigo de periódico]
      We have finally measured the evolutionary rate of cooling of the pulsating hydrogen atmosphere (DA) white dwarf ZZ Ceti (Ross 548), as reflected by the drift rate of the 213.13260694 s period. Using 41 yr of time-series ...
    • Measuring the evolution of the most stable optical clock G 117-B15A 

      Kepler, Souza Oliveira; Costa, Jose Eduardo da Silveira; Castanheira, Bárbara Garcia; Winget, Donald Earl; Mullally, Fergal; Nather, R. Edward; Kilic, Mukremin; Von Hippel, Theodore A.; Mukadam, Anjum Shagufta; Sullivan, Denis J. (2005) [Artigo de periódico]
      We report our measurement of the rate of change of period with time (˙P ) for the 215 s periodicity in the pulsating white dwarf G 117-B15A, the most stable optical clock known. After 31 years of observations, we have ...
    • New pulsating db white dwarf stars from the Sloan Digital Sky Survey 

      Nitta, Atsuko; Kleinman, Scot James; Krzesinski, Jerzy; Kepler, Souza Oliveira; Metcalfe, Travis S.; Mukadam, Anjum Shagufta; Mullally, Fergal; Nather, R. Edward; Sullivan, Denis J.; Thompson, S. E.; Winget, Donald Earl (2009) [Artigo de periódico]
      We are searching for new He atmosphere white dwarf pulsators (DBVs) based on the newly found white dwarf stars from the spectra obtained by the Sloan Digital Sky Survey. DBVs pulsate at hotter temperature ranges than their ...
    • SDSS-III : massive spectroscopic surveys of the distant universe, the Milk Way, and extra-solar planetary systems 

      Eisenstein, Daniel, J.; Weinberg, D.H.; Agol, Eric; Aihara, H.; Allende Prieto, Carlos; Anderson, S.F.; Arns, James A.; Aubourg, Éric; Bailey, Stephen; Balbinot, Eduardo; Barkhouser, Robert; Beers, T.C.; Berlind, Andreas A.; Bickerton, S.J.; Bizyaev, D.; Blanton, M.R.; Bochanski, J.J.; Bolton, Adam S.; Bosman, Casey T.; Bovy, Jo; Brandt, W.N.; Breslauer, Ben; Brewington, Howard J.; Brinkmann, Jon; Brown, Peter J.; Brownstein, Joel R.; Burger, Dan; Busca, Nicolas G.; Campbell, Heather; Cargile, Phillip A.; Carithers, William C.; Carlberg, J.K.; Carr, M.A.; Chang, Liang; Chen, Yanmei; Chiappini, C.C.M.; Comparat, Johan; Connolly, Natalia; Cortes, Marina; Croft, Rupert A.C.; Cunha, Katia; Costa, Luiz N. da; Davenport, J.R.A.; Dawson, K.S.; De Lee, Nathan M.; Mello, Gustavo Frederico Porto de; De Simoni, Fernando S.; Dean, Janice; Dhital, S.; Ealet, Anne; Ebelke, Garrett L.; Edmondson, E.M.; Eiting, J.M.; Escoffier, Stephanie; Esposito, Massimiliano; Evans, M.L.; Fan, Xiaohui; Femenía Castellá, B.; Ferreira, Letícia D.; Fitzgerald, Greg; Fleming, S.W.; Font-Ribera, A.; Ford, Eric B.; Frinchaboy, P.M.; García Pérez, Ana Elia; Gaudi, B. S.; Ge, Jian; Ghezzi, Luan; Gillespie, Bruce A.; Gilmore, Gerry; Girardi, Leo Alberto; Gott, J. Richard; Gould, Andrew; Grebel, Eva K.; Gunn, James E.; Hamilton, J.C.; Harding, Paul; Harris, D.W.; Hawley, Suzanne L.; Hearty, Frederick R.; Hennawi, J.F.; González Hernández, Jonay I.; Ho, Shirley; Hogg, D.W.; Holtzman, J.A.; Honscheid, K.; Inada, Naohisa; Ivans, Inese I.; Jiang, L.; Jiang, Peng; Johnson, J.A.; Jordan, Cathy; Jordan, W.P.; Kauffmann, Guinevere; Kazin, Eyal A.; Kirkby, David; Klaene, Mark A.; Knapp, G. R.; Kneib, J.P.; Kochanek, C.S.; Koesterke, L.; Kollmeier, Juna A.; Kron, Richard G.; Lampeitl, Hubert; Lang, Dustin; Lawler, J.E.; Le Goff, Jean-Marc; Lee, B.L.; Lee, Y.S.; Leisenring, J.M.; Lin, Y.-T.; Liu, Jian; Long, Daniel C.; Loomis, Craig P.; Lucatello, Sara; Lundgren, B.; Lupton, R.H.; Ma, Bo; Ma, Zhibo; Macdonald, Nicholas; Mack, C. E.; Mahadevan, Suvrath; Maia, Marcio Antonio Geimba; Majewski, Steven Raymond; Makler, Martín; Malanushenko, E.; Malanushenko, V.; Mandelbaum, Rachel; Maraston, Claudia; Margala, D.; Maseman, P.A.; Masters, K.L.; McBride, Cameron K.; McDonald, Patrick; McGreer, Ian D.; McMahon, Richard G.; Mena Requejo, Olga; Ménard, Brice; Miralda-Escudé, J.; Morrison, H.L.; Mullally, Fergal; Muna, Demitri; Murayama, H.; Myers, A.D.; Naugle, Tracy; Fausti Neto, Angelo; Nguyen, D.C.; Nichol, Robert C.; Nidever, D.L.; O'Connell, Robert West; Ogando, Ricardo L.C.; Olmstead, Matthew D.; Oravetz, Daniel J.; Padmanabhan, N.; Paegert, Martin; Palanque-Delabrouille, Nathalie; Pan, K.; Pandey, Parul; Parejko, J.K.; Pâris, Isabelle; Pellegrini, Paulo Sérgio de Souza; Pepper, J.; Percival, Will J.; Petitjean, P.; Pfaffenberger, Robert; Pforr, J.; Phleps, Stefanie; Pichon, C,; Pieri, Matthew M.; Prada, F.; Price-Whelan, Adrian M.; Raddick, M. Jordan; Ramos, Beatriz H.F.; Reid, I. Neill; Reylé, Céline; Rich, J.; Richards, G.T.; Rieke, G.H.; Rieke, M.J.; Rix, H.-W.; Robin, A.C.; Rocha-Pinto, H.J.; Rockosi, C.M.; Roe, Natalie A.; Rollinde, Emmanuel; Ross, A.J.; Ross, Nicholas P.; Rossetto, Bruno M.; Sánchez, Ariel G.; Santiago, Basilio Xavier; Sayres, Conor; Schiavon, Ricardo P.; Schlegel, David J.; Schlesinger, K.J.; Schmidt, Sarah. J.; Schneider, D.P.; Sellgren, K.; Bradley, Alaina C. Shelden; Sheldon, Erin; Shetrone, M.; Shu, Yiping; Silverman, J.D.; Simmerer, Jennifer; Simmons, Audrey E.; Sivarani, Thirupathi; Skrutskie, M.F.; Slosar, A.; Smee, Stephen; Smith, Verne V.; Snedden, S.A.; Stassun, Keivan G.; Steele, Oliver; Steinmetz, M.; Stockett, Mark H.; Stollberg, Todd; Strauss, Michael A.; Szalay, A.S.; Tanaka, M.; Thakar, Aniruddha; Thomas, D.; Tinker, Jeremy; Tofflemire, Benjamin M.; Tojeiro, R.; Tremonti, Christy A.; Vargas Magaña, Mariana; Verde, Licia; Vogt, N.P.; Wake, D.A.; Wan, Xiaoke; Wang, Ji; Weaver, Benjamin A.; White, M.; White, Simon D. M.; Wilson, J.C.; Wisniewski, J.P.; Wood-Vasey, W.M.; Yanny, Brian; Yasuda, Naoki; Yèche, Christophe; York, Donald G.; Young, E.; Zasowski, G.; Zehavi, I.; Zhao, Bo (2011) [Artigo de periódico]
      Building on the legacy of the Sloan Digital Sky Survey (SDSS-I and II), SDSS-III is a program of four spectroscopic surveys on three scientific themes: dark energy and cosmological parameters, the history and structure of ...
    • 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 ...
    • 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 ...
    • Thirty-five new pulsating DA white dwarf stars 

      Mukadam, Anjum Shagufta; Mullally, Fergal; Nather, R. Edward; Winget, Donald Earl; Von Hippel, Theodore A.; Kleinman, Scot James; Nitta, Atsuko; Krzesinski, Jerzy; Kepler, Souza Oliveira; Kanaan Neto, Antonio Nemer; Koester, Detlev; Sullivan, Denis J.; Homeier, Derek; Thompson, S. E.; Reaves, David Earl; Cotter, C.; Slaughter, D.; Brinkmann, Jon (2004) [Artigo de periódico]
      We present 35 new pulsating DA (hydrogen atmosphere) white dwarf stars discovered from the Sloan Digital Sky Survey (SDSS) and the Hamburg Quasar Survey (HQS). We have acquired high-speed time series photometry of preselected ...
    • 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 ...