Listar Ciencias Exactas y Naturales por tema "Pulsacoes estelares"

Mostrando ítems 1-20 de 77

    • 2006 Whole Earth Telescope observations of GD358 : a new look at the prototype DBV 

      Provencal, Judith L.; Montgomery, Michael Houston; Kanaan Neto, Antonio Nemer; Shipman, Harry L.; Childers, D.; Baran, Andrzej; Kepler, Souza Oliveira; Reed, M. D.; Zhou, Ai-Ying; Eggen, J.; Watson, Todd K.; Winget, Donald Earl; Thompson, S. E.; Riaz, B.; Nitta, Atsuko; Kleinman, Scot James; Crowe, Richard A.; Slivkoff, Jay; Sherard, P.; Purves, Norman G.; Binder, Philippe M.; Knight, R.; Kim, Seung-Lee; Chen, Wen-Ping; Yang, M.; Lin, Hung-Chin; Lin, Chien-Cheng; Chen, C.-W.; Jiang, Xiaojun; Sergeev, A.; Mkrtichian, David; Andreev, M.; Janulis, Rimvydas; Siwak, Michal; Zola, Staszek; Koziel-Wierzbowska, Dorota; Stachowski, G.; Paparo, Margit; Bognár, Zsófia; Handler, Gerald; Lorenz, Denise; Steininger, Bruno; Beck, Paul; Nagel, Thorsten; Kusterer, D.; Hoffman, A.; Reiff, E.; Kowalski, R.; Vauclair, Gérard; Charpinet, Stéphane; Chevreton, Michel; Solheim, Jan-Eric; Pakstiene, Erika; Fraga, Luciano; Dalessio, J. (2009) [Artículo de periódico]
      We report on the analysis of 436.1 hr of nearly continuous high-speed photometry on the pulsating DB white dwarf GD358 acquired with the Whole Earth Telescope (WET) during the 2006 international observing run, designated ...

    • About the existence of warm H-rich pulsating white dwarfs 

      Althaus, Leandro Gabriel; Córsico, Alejandro Hugo; Uzundag, Murat; Vuckovic, Maja; Baran, Andrzej; Bell, Keaton; Camisassa, María E.; Calcaferro, Leila Magdalena; De Gerónimo, Francisco Cesar; Kepler, Souza Oliveira; Silvotti, Roberto (2020) [Artículo de periódico]
      Context. The possible existence of warm (Teff ∼ 19 000 K) pulsating DA white dwarf (WD) stars, hotter than ZZ Ceti stars, was predicted in theoretical studies more than 30 yr ago. These studies reported the occurrence of ...

    • 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 ...

    • An empirical test of the theory of crystallization in stellar interiors 

      Winget, Donald Earl; Kepler, Souza Oliveira; Kanaan Neto, Antonio Nemer; Montgomery, Michael Houston; Giovannini Junior, Odilon (1997) [Artículo de periódico]
      Our theoretical calculations indicate that the massive pulsating DA white dwarf, BPM 37093, has a crystallized ion interior. Our estimates for the crystallized mass fraction depend on our assumption for the interior ...

    • An observational limit to the evolutionary time scale of the 13,000 K white dwarf G117-B15A 

      Kepler, Souza Oliveira; Vauclair, Gérard; Dolez, Noël; Chevreton, Michel; Barstow, Martin A.; Nather, R. Edward; Winget, Donald Earl; Provencal, Judith L.; Clemens, J. Christopher; Fontaine, Gilles (1990) [Artículo de periódico]
      Nature has provided us with a way of measuring the evolutionary time scale of some stars through aster­ oseismology, i.e., the study of stellar interiors through their intrinsic variations in brightness. By measuring the ...

    • Asteroseismological study of massive ZZ Ceti stars with fully evolutionary models 

      Romero, Alejandra Daniela; Kepler, Souza Oliveira; Córsico, Alejandro Hugo; Althaus, Leandro Gabriel; Fraga, Luciano (2013) [Artículo de periódico]
      We present the first asteroseismological study for 42 massive ZZ Ceti stars based on a large set of fully evolutionary carbon–oxygen core DA white dwarf models characterized by a detailed and consistent chemical inner ...

    • Asteroseismology of a star cooled by neutrino emission : the pulsating pre-white dwarf PG 0122+200 

      O'Brien, M. Sean; Vauclair, Gérard; Kawaler, Steven D.; Watson, Todd K.; Winget, Donald Earl; Nather, R. Edward; Montgomery, Michael Houston; Nitta, Atsuko; Kleinman, Scot James; Sullivan, Denis J.; Jiang, Xiaojun; Marar, T.M. Krishnan; Seetha, S.; Ashoka, B.N.; Bhattacharya, J.; Leibowitz, Elia M.; Hemar, Shirley; Ibbetson, Peter A.; Warner, B.; Van Zyl, L.; Moskalik, Pawel; Zola, Staszek; Pajdosz, Gabriel; Krzesinski, Jerzy; Dolez, Noël; Chevreton, Michel; Solheim, Jan-Eric; Thomassen, T.; Kepler, Souza Oliveira; Giovannini Junior, Odilon; Provencal, Judith L.; Wood, Matthew A.; Clemens, J. Christopher (1998) [Artículo de periódico]
      Observation of g-mode pulsations in the variable pre-white dwarf (GW Virginis) stars provides a unique means to probe their interiors and to study the late stages of stellar evolution. Multisite campaigns have in several ...

    • Asteroseismology of RXJ 2117+3412, the hottest pulsating PG 1159 star 

      Vauclair, Gérard; Moskalik, Pawel; Pfeiffer, Ben; Chevreton, Michel; Dolez, Noël; Serre, B.; Kleinman, Scot James; Barstow, Martin A.; Sansom, A.E.; Solheim, Jan-Eric; Belmonte, J.A.; Kawaler, Steven D.; Kepler, Souza Oliveira; Kanaan Neto, Antonio Nemer; Giovannini Junior, Odilon; Winget, Donald Earl; Watson, Todd K.; Nather, R. Edward; Clemens, J. Christopher; Provencal, Judith L.; Dixson, James S.; Yanagida, K.; Nitta, Atsuko; Montgomery, Michael Houston; Klumpe, Eric W.; Bruvold, A.; O'Brien, M. Sean; Hansen, Carl J.; Grauer, Albert D.; Bradley, Paul A.; Wood, Matthew A.; Achilleos, Nicholas; Jiang, Shi Yang; Fu, Jianning Ning; Marar, T.M. Krishnan; Ashoka, B.N.; Meistas, Edmundas G.; Chernyshev, A.V.; Mazeh, Tsevi; Leibowitz, Elia M.; Hemar, Shirley; Krzesinski, Jerzy; Pajdosz, Gabriel; Zola, Staszek (2002) [Artículo de periódico]
      The pulsating PG 1159 planetary nebula central star RXJ 2117+3412 has been observed over three successive seasons of a multisite photometric campaign. The asteroseismological analysis of the data, based on the 37 identified ...

    • 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 ...

    • Asteroseismology of ZZ Ceti stars with full evolutionary white dwarf models : II. The impact of AGB thermal pulses on the asteroseismic inferences of ZZ Ceti stars 

      De Gerónimo, Francisco Cesar; Althaus, Leandro Gabriel; Córsico, Alejandro Hugo; Romero, Alejandra Daniela; Kepler, Souza Oliveira (2018) [Artículo de periódico]
      Context. The thermally pulsing phase on the asymptotic giant branch (TP-AGB) is the last nuclear burning phase experienced by most low- and intermediate-mass stars. During this phase, the outer chemical stratification above ...

    • Asteroseismology of ZZ Ceti stars with fully evolutionary white dwarf models : I. the impact of the uncertainties from prior evolution on the period spectrum 

      De Gerónimo, Francisco Cesar; Althaus, Leandro Gabriel; Córsico, Alejandro Hugo; Romero, Alejandra Daniela; Kepler, Souza Oliveira (2017) [Artículo de periódico]
      Context. ZZ Ceti stars are pulsating white dwarfs with a carbon-oxygen core build up during the core helium burning and thermally pulsing Asymptotic Giant Branch phases. Through the interpretation of their pulsation periods ...

    • Comparing the asteroseismic properties of pulsating extremely low-mass pre-white dwarf stars and δ Scuti stars 

      Sánchez Arias, J. P.; Córsico, Alejandro Hugo; Romero, Alejandra Daniela; Althaus, Leandro Gabriel (2017) [Artículo de periódico]
      We present the first results of a detailed comparison between the pulsation properties of pulsating Extremely Low-Mass pre-white dwarf stars (the pre-ELMV variable stars) and δ Scuti stars. The instability domains of these ...

    • Comparing the asteroseismic properties of pulsating pre-extremely low mass white dwarf and δ Scuti stars 

      Sánchez Arias, J. P.; Romero, Alejandra Daniela; Córsico, Alejandro Hugo; Pelisoli, Ingrid Domingos; Antoci, Victoria L.; Kepler, Souza Oliveira; Althaus, Leandro Gabriel; Corti, Mariela Alejandra (2018) [Artículo de periódico]
      Context. Pulsating extremely low-mass pre-white dwarf stars (pre-ELMV), with masses between ~0.15 M⊙ and ~0.30 M⊙, constitute a new class of variable stars showing g- and possibly p-mode pulsations with periods between 320 ...

    • 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 ...

    • 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) [Artículo 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 - ...

    • Direct measurement of a secular pulsation period change in the pulsating hot pre-white dwarf PG 1159-035 

      Costa, Jose Eduardo da Silveira; Kepler, Souza Oliveira; Winget, Donald Earl (1999) [Artículo de periódico]
      GW Vir (PG 1159[035) is the prototype of the class of multiperiodic, nonradially pulsating hot white dwarfs, and shows a strong pulsation mode at 516 s. All measurements to date of the secular variation of the 516 s pulsation ...

    • Discovery of 74 new bright ZZ Ceti stars in the first three years of TESS 

      Romero, Alejandra Daniela; Kepler, Souza Oliveira; Hermes, James J.; Amaral, Larissa Antunes; Uzundag, Murat; Bognár, Zsófia; Bell, Keaton; Vanwyngarden, Madison; Baran, Andy; Pelisoli, Ingrid Domingos; Rosa, Gabriela Oliveira da; Koester, Detlev; Klippel, Theylor Schumacher; Fraga, Luciano; Bradley, Paul A.; Vuckovic, Maja; Heintz, Tyler M.; Reding, Joshua S.; Kaiser, B. C.; Charpinet, Stéphane (2022) [Artículo de periódico]
      We report the discovery of 74 new pulsating DA white dwarf stars, or ZZ Cetis, from the data obtained by the Transiting Exoplanet Survey Satellite mission, from Sectors 1 to 39, corresponding to the first 3 cycles. This ...

    • Discovery of an ultramassive pulsating white dwarf 

      Hermes, James J.; Kepler, Souza Oliveira; Castanheira, Bárbara Garcia; Gianninas, Alexandros; Winget, Donald Earl; Montgomery, Michael Houston; Brown, Warren R.; Harrold, Samuel T. (2013) [Artículo de periódico]
      We announce the discovery of themostmassive pulsating hydrogen-atmosphere white dwarf (WD) ever discovered, GD 518. Model atmosphere fits to the optical spectrum of this star show it is a 12,030 ± 210 K WD with a log g = ...

    • Discovery of five new massive pulsating white dwarf stars 

      Castanheira, Bárbara Garcia; Kepler, Souza Oliveira; Kleinman, Scot James; Nitta, Atsuko; Fraga, Luciano (2013) [Artículo de periódico]
      Using the SOuthern Astrophysical Research telescope (SOAR) Optical Imager at the SOAR 4.1 m telescope, we report on the discovery of five new massive pulsating white dwarf stars. Our results represent an increase of about ...