Authors

Donald E. Winget, University of Texas at AustinFollow
R. Edward Nather, University of Texas at AustinFollow
J. Christopher Clemens, University of Texas at AustinFollow
Judith Provencal, University of Texas at AustinFollow
Scot J. Kleinman, University of Texas at AustinFollow
Paul A. Bradley, University of Texas at AustinFollow
Matt A. Wood, University of Texas at AustinFollow
Charles F. Claver, University of Texas at AustinFollow
Marian L. Frueh, University of Texas at Austin
Albert D. Grauer, University of Arkansas at Little RockFollow
Butler P. Hine, NASA Ames Research CenterFollow
Carl J. Hansen, University of Colorado
Gilles Fontaine, Université de Montréal
Nicholas Achilleos, Australian National University
Dayal T. Wickramasinghe, Australian National University
T.M.K. Marar, Indian Space Research Organization
S. Seetha, Indian Space Research Organization
B. N. Ashoka, Indian Space Research Organization
Darragh O'Donoghue, University of Cape TownFollow
Brian Warner, University of Cape TownFollow
Donald W. Kurtz, University of Cape Town
David A. Buckley, University of Cape Town
J. Brickhill, University of Cape Town
Gerard Vauclair, Observatoire Midi-PyreneesFollow
Noël Dolez, Observatoire Midi-Pyrenees
Michel Chevreton, Observatoire de Paris-MeudonFollow
Martin A. Barstow, University of Leicester
Jan-Erik Solheim, Universitet i Tromso
Antonio Kanaan, Universidade Federal do Rio Grande do Sul
Kepler de Souza Oliveira Filho, Universidade Federal do Rio Grande do SulFollow
Gregory W. Henry, Tennessee State UniversityFollow
Steven D. Kawaler, Iowa State University

Document Type

Article

Publication Date

9-1991

Abstract

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 from roughly 1000 to 2600 μHz (1000 s to 385 s periods). This power is completely resolved into 125 individual frequencies; we have identified 101 of them with specific, quantized pulsation modes, and the rest are completely consistent with such modal assignment. The luminosity variations are therefore certainly the result of g-mode pulsations. Although the amplitudes of some of the peaks exhibit significant variations on time scales of a year or so, the underlying frequency structure of the pulsations is stable over much longer intervals. With the help of existing linear theory we use these identifications to determine, or strongly constrain, many of the fundamental physical parameters describing this star. We find its mass to be 0.586 M⊙, its rotation period 1.38 days, its magnetic field less than 6000 G, its pulsation and rotation axes to be aligned, and its outer layers to be compositionally stratified. With straightforward extensions of existing theory it may be possible to determine uniquely from this data set all of the parameters necessary to construct a quantitative model of its interior. These observations also reveal several interesting phenomena that challenge the current theory of nonradial pulsations, and may require substantial new developments to describe them.

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