Navegação Ciências Exatas e da Terra por Assunto "Oscilacoes"

Resultados 1-17 de 17

    • Bpm 24754 : a new southern zz ceti star 

      Giovannini Junior, Odilon; Kepler, Souza Oliveira; Kanaan Neto, Antonio Nemer; Costa, A.F.M.; Koester, Detlev (1998) [Artigo de periódico]
      We report the discovery of a new long{period ZZ Ceti star through the analysis of photometric time series gathered on 7 nights between 1995 and 1996. The light curve displays a periodic variation with a period of ~ 18 min ...

    • Coherence and incoherence in extended broadband triplet interaction 

      Oliveira, Glaucius Iahnke de; Rizzato, Felipe Barbedo (2008) [Artigo de periódico]
      We study the transition from coherent to incoherent dynamics in a nonlinear triplet of broadband combs of waves. Expanding the analysis of previous works, we investigate what happens when the band of available modes is ...

    • Disperson relation and the dielectric tensor for magnetized plasmas with inhomogeneous magnetic field 

      Gaelzer, Rudi; Schneider, Ruth de Souza; Ziebell, Luiz Fernando (1995) [Artigo de periódico]
      We investigate the dispersion relation for a magnetized plasma with weak magnetic field gradients perpendicular to the ambient magnetic field. An explicit expression for the effective dielectric tensor is derived, incorporating ...

    • Einstein A coefficients, oscillator strengths and lifetimes for some selected triplet-triplet transitions of N2 : a comparison between theory and experiment 

      Francke Sandoval, Ricardo Eugenio; Gallas, Jason Alfredo Carlson; Grieneisen, Hans Peter Henrik; Schifino, Jose; Chakraborty, Bijoy P. (1980) [Artigo de periódico]
      Einstein A coefficients, oscillator strengths and lifetimes have been calculated by an asymptotic expansion method, introduced by Chang and Karplus, for the N2, B 3Πg→A 3Σ+u (first positive), C 3Πu→B 3Πg (second positive), ...

    • Globally synchronized oscillations in complex cyclic games 

      Rulquin, Charlotte Rose Gisele; Arenzon, Jeferson Jacob (2014) [Artigo de periódico]
      The rock-paper-scissors game and its generalizations with S > 3 species are well-studied models for cyclically interacting populations. Four is, however, the minimum number of species that, by allowing other interactions ...

    • 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 ...

    • On the systematics of asteroseismological mass determinations of PG 1159 stars 

      Córsico, Alejandro Hugo; Althaus, Leandro Gabriel; Kepler, Souza Oliveira; Costa, Jose Eduardo da Silveira; Miller Bertolami, Marcelo Miguel (2008) [Artigo de periódico]
      Aims. We analyze systematics in the asteroseismological mass determination methods in pulsating PG 1159 stars. Methods. We compare the seismic masses resulting from the comparison of the observed mean period spacings with ...

    • Partial synchronization and spontaneous spatial ordering in coupled chaotic systems 

      Ying, Zhang; Gang, Hu; Cerdeira, Hilda A.; Shigang, Chen; Braun, Thomas; Yugui, Yao (2001) [Artigo de periódico]
      A model of many symmetrically and locally coupled chaotic oscillators is studied. Partial chaotic synchronizations associated with spontaneous spatial ordering are demonstrated. Very rich patterns of the system are revealed, ...

    • Propagação das ondas marítimas e dos tsunami 

      Silveira, Fernando Lang da; Varriale, Maria Cristina (2005) [Artigo de periódico]
      Neste artigo tratamos da propagação das ondas marítimas em geral (ondas de gravidade) e dos tsunami em especial. Mostra-se que, a partir de alguns resultados básicos da teoria, importantes aspectos qualitativos e práticos ...

    • Stability of the envelope evolution of a cold-fluid corkscrewing elliptic beam in a uniform-focusing magnetic field 

      Roytershteyn, Vadim; Chen, Chiping; Pakter, Renato (2003) [Artigo de periódico]
      The envelope oscillations of a cold-fluid corkscrewing elliptic beam in a uniform-focusing magnetic field are studied. In particular, by linearizing the generalized beam envelope equations, the eigenmodes of small-amplitude ...

    • 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 ...

    • 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 rate of cooling of the pulsating white dwarf star G117−B15A : a new asteroseismological inference of the axion mass 

      Córsico, Alejandro Hugo; Althaus, Leandro Gabriel; Bertolami, Marcelo Miguel Miller; Romero, Alejandra Daniela; García-Berro, Enrique; Isern, J.; Kepler, Souza Oliveira (2012) [Artigo de periódico]

    • Toward ensemble asteroseismology of ZZ Ceti stars with fully evolutionary models 

      Romero, Alejandra Daniela; Córsico, Alejandro Hugo; Althaus, Leandro Gabriel; Kepler, Souza Oliveira; Castanheira, Bárbara Garcia; Bertolami, Marcelo Miguel Miller (2012) [Artigo de periódico]
      ZZ Ceti stars form the most numerous group of degenerate variable stars. They are otherwise normal DA (H-rich atmospheres) white dwarfs that exhibit pulsations. Here, we present an asteroseismological analysis for 44 bright ...

    • Towards a pure ZZ Ceti instability strip 

      Castanheira, Bárbara Garcia; Kepler, Souza Oliveira; Costa, Alex Fabiano Murillo da; Giovannini Junior, Odilon; Robinson, E.L.; Winget, Donald Earl; Kleinman, Scot James; Nitta, Atsuko; Eisenstein, D.J.; Koester, Detlev; Santos, Marcio Gabriel dos (2007) [Artigo de periódico]
      Context. We have observed again two stars inside the ZZ Ceti instability strip that were previously classified as not-observed-to-vary (NOV) by Mukadam et al. (2004) and found them to be low-amplitude variables. Some ...

    • 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 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) [Artigo 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 ...