Navegação Ciências Exatas e da Terra por Autor "Mukadam, Anjum Shagufta"

Resultados 1-17 de 17

    • Amplitude and frequency variability of the pulsating DB white dwarf stars KUV 05134+2605 and PG 1654+160 observed with the Whole Earth Telescope 

      Handler, Gerald; O'Donoghue, Darragh; Muller, M.; Solheim, Jan-Eric; Gonzalez Perez, Jose Miguel; Johannessen, F.; Paparo, Margit; Szeidl, Bela; Virághalmy, Géza; Silvotti, Roberto; Vauclair, Gérard; Dolez, Noël; Pallier, E.; Chevreton, Michel; Kurtz, Donald W.; Bromage, Gordon E.; Cunha, Margarida S.; Ostensen, Roy; Fraga, Luciano; Kanaan Neto, Antonio Nemer; Amorim, André; Giovannini Junior, Odilon; Kepler, Souza Oliveira; Costa, Alex Fabiano Murillo da; Anderson, R.F.; Wood, Matthew A.; Silvestri, Nicole M.; Klumpe, Eric W.; Carlton, Robert F.; Miller, Hugh Richard; McFarland, John P.; Grauer, Albert D.; Kawaler, Steven D.; Riddle, Reed L.; Reed, M. D.; Nather, R. Edward; Winget, Donald Earl; Hill, J.A.; Metcalfe, Travis S.; Mukadam, Anjum Shagufta; Kilic, Mukremin; Watson, Todd K.; Kleinman, Scot James; Nitta, Atsuko; Guzik, Joyce Ann; Bradley, Paul A.; Sekiguchi, Kazuhiro; Sullivan, Denis J.; Sullivan, Terry; Shobbrook, Robert R.; Jiang, Xiaojun; Birch, P.; Ashoka, B.N.; Seetha, S.; Girish, V.; Joshi, Santosh; Dorokhova, Tatyana N.; Dorokhov, N.I.; Akan, Mustafa Can; Meistas, Edmundas G.; Janulis, Rimvydas; Kalytis, Romualdas; Alisauskas, Darius; Anguma, S.K.; Kalebwe, P.C.; Moskalik, Pawel; Ogloza, Waldemar; Stachowski, G.; Pajdosz, Gabriel; Zola, Staszek (2003) [Artigo de periódico]
      We have acquired new time series photometry of the two pulsating DB white dwarf stars KUV 05134+2605 and PG 1654+160 with the Whole Earth Telescope. Additional single-site photometry is also presented. We use all these ...

    • 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 the 'missing' mode in HR 1217 by the Whole Earth Telescope 

      Kurtz, Donald W.; Kawaler, Steven D.; Riddle, Reed L.; Reed, M. D.; Cunha, Margarida S.; Wood, Matthew A.; Silvestri, Nicole M.; Watson, Todd K.; Dolez, Noël; Moskalik, Pawel; Zola, Staszek; Pallier, E.; Guzik, Joyce Ann; Metcalfe, Travis S.; Mukadam, Anjum Shagufta; Nather, R. Edward; Winget, Donald Earl; Sullivan, Denis J.; Sullivan, Terry; Sekiguchi, Kazuhiro; Jiang, Xiaojun; Shobbrook, Robert R.; Ashoka, B.N.; Seetha, S.; Joshi, Santosh; O'Donoghue, Darragh; Handler, Gerald; Mueller, M.; Gonzalez Perez, Jose Miguel; Solheim, Jan-Eric; Johannessen, F.; Ulla, Ana; Kepler, Souza Oliveira; Kanaan Neto, Antonio Nemer; Costa, Alex Fabiano Murillo da; Fraga, Luciano; Giovannini Junior, Odilon; Matthews, Jaymie M.; WET collaboration (2002) [Artigo de periódico]
      HR1217 is a prototypical rapidly oscillating Ap star that has presented a test to the theory of non-radial stellar pulsation. Prior observations showed a clear pattern of five modes with alternating frequency spacings of ...

    • Ensemble characteristics of the ZZ Ceti stars 

      Mukadam, Anjum Shagufta; Montgomery, Michael Houston; Winget, Donald Earl; Kepler, Souza Oliveira; Clemens, J. Christopher (2006) [Artigo de periódico]
      We present the observed pulsation spectra of all known noninteracting ZZ Ceti stars (hydrogen atmosphere white dwarf variables [DAVs]) and examine changes in their pulsation properties across the instability strip.We confirm ...

    • Evidence for temperature change and oblique pulsation from light curve fits of the pulsating white dwarf GD 358 

      Montgomery, Michael Houston; Provencal, Judith L.; Kanaan Neto, Antonio Nemer; Mukadam, Anjum Shagufta; Thompson, S. E.; Dalessio, J.; Shipman, Harry L.; Winget, Donald Earl; Kepler, Souza Oliveira; Koester, Detlev (2010) [Artigo de periódico]
      Convective driving, the mechanism originally proposed by Brickhill for pulsating white dwarf stars, has gained general acceptance as the generic linear instability mechanism in DAV and DBV white dwarfs. This physical ...

    • Evolutionary timescale of the pulsating white dwarf G117-B15A : the most stable optical clock known 

      Kepler, Souza Oliveira; Mukadam, Anjum Shagufta; Winget, Donald Earl; Nather, R. Edward; Metcalfe, Travis S.; Reed, M. D.; Kawaler, Steven D.; Bradley, Paul A. (2000) [Artigo de periódico]
      We observe G117-B15A, the most precise optical clock known, to measure the rate of change of the main pulsation period of this blue-edge DAV white dwarf. Even though the obtained value is only within 1 σ, P = (2.3±1.4) x ...

    • 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 ...

    • A new ZZ Ceti white dwarf pulsator : G30-20 

      Mukadam, Anjum Shagufta; Kepler, Souza Oliveira; Winget, Donald Earl; Bergeron, P. (2002) [Artigo de periódico]
      We report the discovery of a new hydrogen atmosphere variable white dwarf (DAV; ZZ Ceti), G30-20, a high-amplitude, long-period pulsator. The Fourier transform of its light curve shows power around 1050–1125 s. We suspect ...

    • Pushing the ground-based limit : 14-μmag photometric precision with the definitive Whole Earth Telescope asteroseismic data set for the rapidly oscillating Ap star HR 1217 

      Kurtz, Donald W.; Cameron, C.; Cunha, Margarida S.; Dolez, Noël; Vauclair, Gérard; Pallier, E.; Ulla, Ana; Kepler, Souza Oliveira; Costa, Alex Fabiano Murillo da; Kanaan Neto, Antonio Nemer; Fraga, Luciano; Giovannini Junior, Odilon; Wood, Matthew A.; Silvestri, Nicole M.; Kawaler, Steven D.; Riddle, Reed L.; Reed, M. D.; Watson, Todd K.; Metcalfe, Travis S.; Mukadam, Anjum Shagufta; Nather, R. Edward; Winget, Donald Earl; Nitta, Atsuko; Kleinman, Scot James; Guzik, Joyce Ann; Bradley, Paul A.; Matthews, Jaymie M.; Sekiguchi, Kazuhiro; Sullivan, Denis J.; Sullivan, Terry; Shobbrook, Robert R.; Jiang, Xiaojun; Birch, P.; Ashoka, B.N.; Seetha, S.; Girish, V.; Joshi, Santosh; Moskalik, Pawel; Zola, Staszek; O'Donoghue, Darragh; Handler, Gerald; Mueller, M.; Gonzalez Perez, Jose Miguel; Solheim, Jan-Eric; Johannessen, F.; Bigot, L. (2005) [Artigo de periódico]
      HR1217 is one of the best-studied rapidly oscillating Ap (roAp) stars, with a frequency spectrum of alternating even-and odd-l modes that are distorted by the presence of a strong, global magnetic field. Several recent ...

    • 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 ...

    • The everchanging pulsating white dwarf GD358 

      Kepler, Souza Oliveira; Nather, R. Edward; Winget, Donald Earl; Nitta, Atsuko; Kleinman, Scot James; Metcalfe, Travis S.; Sekiguchi, Kazuhiro; Jiang, Xiaojun; Sullivan, Denis J.; Sullivan, Terry; Janulis, Rimvydas; Meistas, Edmundas G.; Kalytis, Romualdas; Krzesinski, Jerzy; Ogloza, Waldemar; Zola, Staszek; O'Donoghue, Darragh; Romero-Colmenero, Encarni; Martinez, Peter; Dreizler, Stefan; Deetjen, Jochen L.; Nagel, Thorsten; Schuh, Sonja L.; Vauclair, Gérard; Fu, Jianning Ning; Chevreton, Michel; Solheim, Jan-Eric; Gonzalez Perez, Jose Miguel; Johannessen, F.; Kanaan Neto, Antonio Nemer; Costa, Jose Eduardo da Silveira; Costa, Alex Fabiano Murillo da; Wood, Matthew A.; Silvestri, Nicole M.; Ahrens, T.J.; Jones, Aaron Kyle; Collins, A.E.; Boyer, M.; Shaw, James Scott; Mukadam, Anjum Shagufta; Klumpe, Eric W.; Larrison, Jesse; Kawaler, Steven D.; Riddle, Reed L.; Ulla, Ana; Bradley, Paul A. (2003) [Artigo de periódico]
      We report 323 hours of nearly uninterrupted time series photometric observations of the DBV star GD 358 acquired with the Whole Earth Telescope (WET) during May 23rd to June 8th, 2000. We acquired more than 232 000 independent ...

    • 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 ...

    • 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 ...

    • 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, ...