• 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 ...
    • 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 ...
    • Redefining the empirical ZZ Ceti instability strip 

      Mukadam, Anjum Shagufta; Winget, Donald Earl; Von Hippel, Theodore A.; Montgomery, Michael Houston; Kepler, Souza Oliveira; Costa, Alex Fabiano Murillo da (2004) [Artigo de periódico]
      We use the new ZZ Ceti stars (hydrogen-atmosphere white dwarf variables; DAVs) discovered within the Sloan Digital Sky Survey (Mukadam et al. 2004) to redefine the empirical ZZ Ceti instability strip. This is the first ...
    • 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 ...