Listar Ciencias Exactas y Naturales por autor "Kurtz, Donald W."
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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) [Artículo 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 ... -
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) [Artículo 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 ... -
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) [Artículo 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) [Artículo 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 ... -
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) [Artículo 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 ... -
Phase instability and non-linearity in the distorted dipole pulsation mode of the rapidly oscillating ap star hr 3831 (hd 83368)
Kurtz, Donald W.; Kanaan Neto, Antonio Nemer; Martinez, Peter (1993) [Artículo de periódico]HR 3831 is a rapidly oscillating A7p SrCrEu star with Telf = 8000 K, R= 1.9 R̛, Mv=2.0, V=6.168, d ~~ 60 pc, a magnetic field which ranges from about -720 G ≤ Belf ≤ +780 G with the rotation period of 2.851982 d, and a ... -
Pulsation in the white dwarf HE 1017−1352
Romero, Alejandra Daniela; Amaral, Larissa Antunes; Kepler, Souza Oliveira; Fraga, Luciano; Kurtz, Donald W.; Shibahashi, Hiromoto (2020) [Artículo de periódico]We report the detection of periodic variations on the Teff 32 000 K DA white dwarf star HE 1017−1352. We obtained time series photometry using the 4.1-m Southern Astrophysical Research telescope on three separate nights ... -
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) [Artículo 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 ... -
A refinement of the rotation period of the roap star hr 3831 and the discovery of a significant phase lag between the times of pulsation and magnetic extrema and the time of mean-light extremum
Kurtz, Donald W.; Kanaan Neto, Antonio Nemer; Martinez, Peter; Tripe, P. (1992) [Artículo de periódico]HR 3831 is a rapidly oscillating Ap star with a pulsational period of 11.67 min. The amplitude of this pulsation ranges from O to about 5 mmag as a function of the rotational aspect of the star. We use 268 hr of new ... -
The high-overtone p-mode spectrum of the rapidly oscillating Ap star HR 1217 (HD 24712) - results of a frequency analysis of 324 hr of multi-site photometric observations obtained during a 46-d time-span in 1986
Kurtz, Donald W.; Mattews, J.M.; Martinez, Peter; Seeman, J.; Crooper, Mark; Clemens, J. Christopher; Kreidl, T.J.; Sterken, C.; Schneider, H.; Weiss, W.W.; Kawaler, Steven D.; Kepler, Souza Oliveira (1989) [Artículo de periódico]We present new high-speed photometric observations of the rapidly oscillating Ap star HR 1217 obtained during 365 hr of observation at eight observations in 1986 October, November and December. We show that the 6-min light ... -
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) [Artículo 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 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) [Artículo 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 ... -
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) [Artículo 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) [Artículo 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 ...