Navegação Ciências Exatas e da Terra por Autor "Claver, C.F."

Resultados 1-16 de 16

    • Asteroseismology of the dov star PG 1159-035 with the Whole Earth Telescope 

      Winget, Donald Earl; Hansen, Carl J.; Fontaine, Gilles; Achilleos, Nicholas; Wickramasinghe, D.T.; Marar, T.M. Krishnan; Seetha, S.; Ashoka, B.N.; O'Donoghue, Darragh; Warner, B.; Kurtz, Donald W.; Buckley, David A.H.; Brickhill, J.; Vauclair, Gérard; Dolez, Noël; Chevreton, Michel; Barstow, Martin A.; Solheim, Jan-Eric; Kanaan Neto, Antonio Nemer; Hine, B.P.; Grauer, Albert D.; Frueh, M.L.; Claver, C.F.; Wood, Matthew A.; Bradley, Paul A.; Kleinman, Scot James; Provencal, Judith L.; Clemens, J. Christopher; Nather, R. Edward (1991) [Artigo de periódico]
      We report the results from 264.1 hr of nearly continuous time-series photometry on the pulsating pre-white dwarf star (DOV) PG 1159-035. The high-resolution power spectrum of this data set is dominated by power in the range ...

    • 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 ...

    • A detection of the evolutionary time scale of the da white dwarf G117-B15A with the Whole Earth Telescope 

      Kepler, Souza Oliveira; Winget, Donald Earl; Nather, R. Edward; Bradley, Paul A.; Grauer, Albert D.; Fontaine, Gilles; Bergeron, Pierre; Vauclair, Gérard; Claver, C.F.; Marar, T.M. Krishnan; Seetha, S.; Ashoka, B.N.; Mazeh, Tsevi; Leibowitz, Elia M.; Dolez, Noël; Chevreton, Michel; Barstow, Martin A.; Clemens, J. Christopher; Kleinman, Scot James; Sansom, A.E.; Tweedy, R.W.; Hine, B.P.; Provencal, Judith L.; Wesemael, F.; Wood, Matthew A.; Brassard, P.; Solheim, Jan-Eric; Emanuelsen, P.-I.; Kanaan Neto, Antonio Nemer; Kepler, Souza Oliveira (1991) [Artigo de periódico]
      We have detected the time rate of change for the main pulsation period of the 13,000 K DA white dwarf G117-B15A, using the Whole Earth Telescope (WET). The observed rate of period change, P = (12.0 ± 3.5) x 10- 15 s s - ...

    • High-speed photometric observations of the pulsating da white dwarf gd 165 

      Bergeron, Pierre; Fontaine, Gilles; Brassard, P.; Lamontagne, R.; Wesemael, F.; Winget, Donald Earl; Nather, R. Edward; Bradley, Paul A.; Claver, C.F.; Clemens, J. Christopher; Kleinman, Scot James; Provencal, Judith L.; Mcgraw, J.T.; Birch, P.; Candy, M.; Buckley, David A.H.; Tripe, P.; Augusteijn, T.; Vauclair, Gérard; Kepler, Souza Oliveira; Kanaan Neto, Antonio Nemer (1993) [Artigo de periódico]
      New high-speed photometric observations ofthe pulsating DA white dwarfGD 165 are presented. The Fourier spectrum ofthe light curve ofGD 165 exhibits two main regions ofpower at 120 and 193 s. The presence of a high-amplitude ...

    • Nonradial pulsation of the unevolved hot (gamma) scuti star cd-24 7599 discovered with the whole earth telescope 

      Handler, Gerald; Breger, M.; Sullivan, Denis J.; Peet, A.J. van der; Clemens, J. Christopher; O'Donoghue, Darragh; Chen, A.-L.; Kanaan Neto, Antonio Nemer; Sterken, C.; Claver, C.F.; Krisciunas, K.; Kleinman, Scot James; Wickramasinghe, D.T.; Wills, Beverley J.; Provencal, Judith L.; Nather, R. Edward; Winget, Donald Earl; Watson, Todd K.; Barstow, Martin A.; Buckley, David A.H. (1996) [Artigo de periódico]
      We report a frequency analysis of the δ Scuti star CD-24°7599 and the discovery that it pulsates nonradially with at least 7 frequencies between 27.01 and 38.11 cycles per day (312 to 441 μHz). These results are based on ...

    • Observational limits on companions to g29-38 

      Kleinman, Scot James; Nather, R. Edward; Winget, Donald Earl; Clemens, J. Christopher; Bradley, Paul A.; Kanaan Neto, Antonio Nemer; Provencal, Judith L.; Claver, C.F.; Watson, Todd K.; Yanagida, K.; Dixson, James S.; Wood, Matthew A.; Sullivan, Denis J.; 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.; Kepler, Souza Oliveira; Giovannini Junior, Odilon; Hansen, Carl J.; Kawaler, Steven D. (1994) [Artigo de periódico]
      Recent interest in the variable (DAV) white dwarf G29-38 has been stirred by a tentative report of a radial velocity variation that may be due to an unseen companion. Earlier evidence for a brown dwarf in the system has ...

    • 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 ...

    • The unusual helium variable AM Canum Venaticorum 

      Provencal, Judith L.; Winget, Donald Earl; Nather, R. Edward; Robinson, E.L.; Solheim, Jan-Eric; Clemens, J. Christopher; Bradley, Paul A.; Kleinman, Scot James; Kanaan Neto, Antonio Nemer; Claver, C.F.; Hansen, Carl J.; Marar, T.M. Krishnan; Seetha, S.; Ashoka, B.N.; Leibowitz, Elia M.; Meistas, Edmundas G.; Bruvold, A.; Vauclair, Gérard; Dolez, Noël; Chevreton, Michel; Barstow, Martin A.; Sansom, A.E.; Tweedy, R.W.; Fontaine, Gilles; Bergeron, Pierre; Kepler, Souza Oliveira; Wood, Matthew A.; Grauer, Albert D. (1995) [Artigo de periódico]
      The unusual variable star AM CVn has puzzled astronomers for over 40 years. This object, both a photometric and spectroscopic variable, is believed to contain a pair of hydrogen-deficient white dwarfs of extreme mass ratio, ...

    • Understanding the cool DA white dwarf pulsator G29-38 

      Kleinman, Scot James; Nather, R. Edward; Winget, Donald Earl; Clemens, J. Christopher; Bradley, Paul A.; Kanaan Neto, Antonio Nemer; Provencal, Judith L.; Claver, C.F.; Watson, Todd K.; Yanagida, K.; Nitta, Atsuko; Dixson, James S.; Wood, Matthew A.; Grauer, Albert D.; Hine, B.P.; Fontaine, Gilles; Liebert, James; Sullivan, Denis J.; Wickramasinghe, D.T.; Achilleos, Nicholas; Marar, T.M. Krishnan; Seetha, S.; Ashoka, B.N.; Meistas, Edmundas G.; Leibowitz, Elia M.; Moskalik, Pawel; Krzesinski, Jerzy; Solheim, Jan-Eric; Bruvold, A.; O'Donoghue, Darragh; Kurtz, Donald W.; Warner, B.; Martinez, Peter; Vauclair, Gérard; Dolez, Noël; Chevreton, Michel; Barstow, Martin A.; Kepler, Souza Oliveira; Giovannini Junior, Odilon; Augusteijn, T.; Hansen, Carl J.; Kawaler, Steven D. (1998) [Artigo de periódico]
      The white dwarfs are promising laboratories for the study of cosmochronology and stellar evolution. Through observations of the pulsating white dwarfs, we can measure their internal structures and compositions, critical ...

    • Whole earth telescope observations and seismological analysis of the cool zz ceti star gd 154 

      Pfeiffer, Ben; Vauclair, Gérard; Dolez, Noël; Chevreton, Michel; Fremy, J. R.; Barstow, Martin A.; Belmonte, J.A.; Kepler, Souza Oliveira; Kanaan Neto, Antonio Nemer; Giovannini Junior, Odilon; Fontaine, Gilles; Bergeron, Pierre; Wesemael, F.; Grauer, Albert D.; Nather, R. Edward; Winget, Donald Earl; Provencal, Judith L.; Clemens, J. Christopher; Bradley, Paul A.; Dixson, James S.; Kleinman, Scot James; Watson, Todd K.; Claver, C.F.; Matzeh, Tsevi; Leibowitz, Elia M.; Moskalik, Pawel (1996) [Artigo de periódico]
      This paper presents the results of high speed photometric observations of the cool variable DA white dwarf (DAV) GD 154 obtained with the Whole Earth Telescope. GD 154 is one of the coolest pulsating DA white dwarfs and ...

    • Whole earth telescope observations of am canum venaticorum-discoseismology at last 

      Solheim, Jan-Eric; Provencal, Judith L.; Bradley, Paul A.; Vauclair, Gérard; Barstow, Martin A.; Kepler, Souza Oliveira; Fontaine, Gilles; Graver, A.D.; Winget, Donald Earl; Marar, T.M. Krishnan; Leibowitz, Elia M.; Enanvelsen, P.I.; Chevreton, Michel; Dolez, Noël; Kanaan Neto, Antonio Nemer; Bergeron, Pierre; Claver, C.F.; Clemens, J. Christopher; Kleinman, Scot James; Hine, B.P.; Seetha, S.; Shoka, B.N.; Mazeh, Tsevi; Sansom, A.E.; Tweedy, P.W.; Meistas, Edmundas G.; Bruvold, A.; Massacand, C.N. (1998) [Artigo de periódico]
      We report the results of 143.2 hours of time-series photometry over a 12 day period for AM CVn (= HZ 29) as part of the Whole Earth Telescope (WET) project.ˡ This star is believed to be an ultra-short period cataclysmic ...

    • Whole Earth Telescope observations of the DAV white dwarf G226-29 

      Kepler, Souza Oliveira; Giovannini Junior, Odilon; Wood, Matthew A.; Nather, R. Edward; Winget, Donald Earl; Kanaan Neto, Antonio Nemer; Kleinman, Scot James; Bradley, Paul A.; Provencal, Judith L.; Clemens, J. Christopher; Claver, C.F.; Watson, Todd K.; Yanagida, K.; Krisciunas, K.; Marar, T.M. Krishnan; Seetha, S.; Ashoka, B.N.; Leibowitz, Elia M.; Mendelson, Haim; Mazeh, Tsevi; Moskalik, Pawel; Krzesinski, Jerzy; Pajdosz, Y.; Zola, Staszek; Solheim, Jan-Eric; Emanuelsen, P.-I.; Dolez, Noël; Vauclair, Gérard; Chevreton, Michel; Fremy, J. R.; Barstow, Martin A.; Sansom, A.E.; Tweedy, R.W.; Wickramasinghe, D.T.; Ferrario, Lilia; Sullivan, Denis J.; Peet, A.J. van der; Buckley, David A.H.; Chen, A.-L. (1995) [Artigo de periódico]
      We observed G226-29 for 121 hr in 1992 February and confirm the presence of the three previously identified frequencies close to 109 s. We find no evidence of other pulsation periods down to our noise level of about 0.35 ...

    • Whole Earth Telescope observations of the DBV white dwarf GD 358 

      Winget, Donald Earl; Nather, R. Edward; Clemens, J. Christopher; Provencal, Judith L.; Kleinman, Scot James; Bradley, Paul A.; Claver, C.F.; Dixson, James S.; Montgomery, Michael Houston; Hansen, Carl J.; Hine, B.P.; Birch, P.; Candy, M.; Marar, T.M. Krishnan; Seetha, S.; Ashoka, B.N.; Leibowitz, Elia M.; O'Donoghue, Darragh; Warner, B.; Buckley, David A.H.; Tripe, P.; Vauclair, Gérard; Dolez, Noël; Chevreton, Michel; Serre, T.; Garrido, R.; Kepler, Souza Oliveira; Kanaan Neto, Antonio Nemer; Augusteijn, T.; Wood, Matthew A.; Bergeron, Pierre; Grauer, Albert D. (1994) [Artigo de periódico]
      We report on the analysis of 154 hours of early continuous high-speed photometry on the pulsating DB white dwarf (DBV) GD 358, obtained during the Whole Earth Telescope (WET) run of 1990 May. The power spectrum of the light ...

    • Whole Earth Telescope observations of the helium interacting binary PG 1346+082 (CR bootis) 

      Provencal, Judith L.; Winget, Donald Earl; Nather, R. Edward; Robinson, E.L.; Clemens, J. Christopher; Bradley, Paul A.; Claver, C.F.; Kleinman, Scot James; Grauer, Albert D.; Hine, B.P.; Ferrario, Lilia; O'Donoghue, Darragh; Warner, B.; Vauclair, Gérard; Chevreton, Michel; Kepler, Souza Oliveira; Wood, Matthew A.; Henry, G.W. (1997) [Artigo de periódico]
      We present our analysis of 240 hr of white-light, high-speed photometry of the dwarf nova-like helium variable PG 1346+082 (CR Boo). We identify two frequencies in the low-state power spectrum, at 679.670±0.004 μHz and ...

    • Whole Earth Telescope observations of the white dwarf G29-38 : phase variations of the 615 second period 

      Winget, Donald Earl; Nather, R. Edward; Clemens, J. Christopher; Provencal, Judith L.; Kleinman, Scot James; Bradley, Paul A.; Wood, Matthew A.; Claver, C.F.; Robinson, E.L.; Grauer, Albert D.; Hine, B.P.; Fontaine, Gilles; Achilleos, Nicholas; Marar, T.M. Krishnan; Seetha, S.; Ashoka, B.N.; O'Donoghue, Darragh; Warner, B.; Kurtz, Donald W.; Martinez, Peter; Vauclair, Gérard; Chevreton, Michel; Augusteijn, T.; Paradijs, J. van; Hansen, Carl J.; Liebert, James; Kanaan Neto, Antonio Nemer; Kepler, Souza Oliveira (1990) [Artigo de periódico]
      Using an extensive set of high-speed photometric observations obtained with the Whole Earth Telescope network, we show that the complex light curve of the ZZ Ceti (DAV) star G29-38 is dominated by a single, constant amplitude ...

    • Whole Earth Telescope observations of V471 Tauri : the nature of the white dwarf variations 

      Clemens, J. Christopher; Nather, R. Edward; Winget, Donald Earl; Robinson, E.L.; Wood, Matthew A.; Claver, C.F.; Provencal, Judith L.; Kleinman, Scot James; Bradley, Paul A.; Frueh, M.L.; Grauer, Albert D.; Hine, B.P.; Fontaine, Gilles; Achilleos, Nicholas; Wickramasinghe, D.T.; Marar, T.M. Krishnan; Seetha, S.; Ashoka, B.N.; O'Donoghue, Darragh; Warner, B.; Kurtz, Donald W.; Martinez, Peter; Vauclair, Gérard; Chevreton, Michel; Barstow, Martin A.; Kanaan Neto, Antonio Nemer; Kepler, Souza Oliveira; Augusteijn, T.; Paradijs, J. van; Hansen, Carl J. (1992) [Artigo de periódico]
      We have conducted time-series photometric observations of the binary star V471 Tauri using the Whole Earth Telescope observing network. Our purpose was to determine the mechanism responsible for causing the 555 and 277 s ...