1. Whole earth telescope observations and seismological analysis of the cool zz ceti star gd 154
- Author
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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., and Moskalik, Pawel
- Subjects
Fotometria ,oscillations [Stars] ,interiors [Stars] ,White dwarfs ,individual (GD 154) [Stars] ,Astrofisica estelar ,Oscilacoes [Estrelas] - Abstract
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 its study is important for understanding the red edge of the ZZ Ceti instability strip. Its power spectrum is dominated by three independent modes (P₁ = 1186.5s, P₂ = 1088.6s and P₃ = 402.6s), and their harmonics and linear combinations. None of the half-integer harmonics reported in previous observations were present during the WET campaign. We propose that the observed modes are trapped in the thin outer hydrogen layers. From the resulting identification of the pulsation modes, one derives an estimate of the rotation period (2.3 days) and of the mass ofthe outer hydrogen layer (2 x 10ˉ¹° M*).
- Published
- 1996