Whole Earth Telescope observations of the pulsating hot white dwarf PG 1707+427

Steven D. Kawaler (1) , E. M. Potter (1) , Maja Vuckovic (1) , Z. E. Dind (2) , Simon J. O'Toole (2) , J. C. Clemens (3) , M. S. O'Brien (4) , A. D. Grauer (5) , R. E. Nather (6) , P. A. Moskalik (7) , C. F. Claver (8) , G. Fontaine (9) , F. Wesemael (9) , P. Bergeron (9) , Gérard Vauclair (10) , N. Dolez (10) , Michel Chevreton (11, 12, 13) , S. J. Kleinman (14) , T. K. Watson (15) , Martin A. Barstow (16) , A. E. Sansom (17) , D. E. Winget (6) , S. O. Kepler (18) , A. Kanaan (19) , P. A. Bradley (20) , J. Dixson (6) , J. L. Provençal (21) , Timothy R. Bedding (2)

1 Department of Physics and Astronomy, Iowa State University
2 School of physics, University of New South Wales
3 Department of Physics and Astronomy, University of North Carolina
4 Department of Astronomy, Yale University
5 Department of Physics and Astronomy, University of Arkansas
6 Department of Astronomy, University of Texas
7 CAMK - Centrum Astronomiczne im. M. Kopernika, Warszawa
8 NOAO - National Optical Astronomy Observatory, Tucson
9 Département de Physique, Université de Montréal
10 OMP - Observatoire Midi-Pyrénées
11 DAEC - Departement d'Astrophysique Extragalactique et de Cosmologie
12 LESIA - Laboratoire d'études spatiales et d'instrumentation en astrophysique
13 Pôle Astronomie du LESIA
14 Apache Point Observatory
15 Southwestern University
16 University of Leicester
17 Isaac Newton Group of Telescopes
18 Instituto de Física, Universidade Federal do Rio Grande do Sul
19 Departamento de Física, Universidade Federal de Santa Catarina
20 LANL - Los Alamos National Laboratory
21 Department of Physics and Astronomy, University of Delaware

We report on the analysis of multisite time-series photometry of the pulsating pre-white dwarf (GW Vir star) PG 1707+427, obtained by the Whole Earth Telescope collaboration. This is the last of the known GW Vir stars without surrounding nebulae to be resolved by multisite data. Successful resolution of the pulsation spectrum resulted from the combination of high signal-to-noise observations with a large telescope and wide coverage in longitude with smaller telescopes. We find a series of 8 pulsation frequencies (along with two nonlinear combination frequencies), and identify 7 of them as part of a sequence of l=1 modes, with a common period spacing of 23.0 s. This spacing implies that the mass of PG 1707+427 is 0.57 M_&sun;. Preliminary model fits suggest that the mass determined via asteroseismology is consistent with the mass determined from spectroscopy combined with evolutionary tracks.

Domaines: Astrophysique [astro-ph]; Planète et Univers [physics]

Steven D. Kawaler, E. M. Potter, Maja Vuckovic, Z. E. Dind, Simon J. O'Toole, et al.. Whole Earth Telescope observations of the pulsating hot white dwarf PG 1707+427. Astronomy and Astrophysics - A&A, 2004, 428, pp.969-981. ⟨10.1051/0004-6361:20041475⟩. ⟨hal-03732809⟩