EDP Sciences
Free access
Issue
A&A
Volume 428, Number 3, December IV 2004
Page(s) 969 - 981
Section Stellar structure and evolution
DOI http://dx.doi.org/10.1051/0004-6361:20041475


A&A 428, 969-981 (2004)
DOI: 10.1051/0004-6361:20041475

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

S. D. Kawaler1, E. M. Potter1, M. Vuckovic1, Z. E. Dind2, S. O'Toole2, 3, J. C. Clemens4, M. S. O'Brien5, A. D. Grauer6, R. E. Nather7, P. A. Moskalik8, C. F. Claver9, G. Fontaine10, F. Wesemael10, P. Bergeron10, G. Vauclair11, N. Dolez11, M. Chevreton12, S. J. Kleinman13, T. K. Watson14, M. A. Barstow15, 16, A. E. Sansom16, 17, D. E. Winget7, S. O. Kepler18, A. Kanaan19, P. A. Bradley20, J. Dixson7, J. Provencal21 and T. R. Bedding2

1  Department of Physics and Astronomy, Iowa State University, Ames, IA 50011, USA
    e-mail: sdk@iastate.edu
2  School of Physics, University of Sydney, Sydney NSW, Australia
3  Dr. Remeis-Sternwarte, Astronomisches Institut der Universität Erlangen-Nürnberg, Sternwartstr. 7, Bamberg 96049, Germany
4  Department of Physics and Astronomy, University of North Carolina, Chapel Hill, NC 27599-3255, USA
5  Department of Astronomy, Yale University, New Haven, CT 06851, USA
6  Department of Physics and Astronomy, University of Arkansas at Little Rock, Little Rock, AR 72204, USA
7  Department of Astronomy, University of Texas, Austin, TX 78712, USA
8  Nicolas Copernicus Astronomical Center, Polish Academy of Sciences, ul. Bartycka 18, 00-716 Warsaw, Poland
9  National Optical Astronomy Observatory, 950 N. Cherry Ave, Tucson, AZ 85719, USA
10  Département de Physique, Université de Montréal, Montréal, Québec, H3C 3J7, Canada
11  Université Paul Sabatier, Observatoire Midi-Pyrénées, 14 avenue E. Belin, 31400 Toulouse, France
12  Observatoire de Paris-Meudon, DAEC, 92195 Meudon, France
13  Apache Point Observatory, PO Box 59, Sunspot, NM 88349, USA
14  Southwestern University, 1001 E. University Avenue, Georgetown, TX 78626, USA
15  Department of Physics and Astronomy, University of Leicester, Leicester LE1 7RH, UK
16  Isaac Newton Group of Telescopes, 37800 Santa Cruz de La Palma, Canary Islands, Spain
17  Centre for Astrophysics, University of Central Lancashire, Preston, Lancashire, PR1 2HE, UK
18  Instituto de Física, UFRGS, Campus do Vale, CP 15051 Porto Alegre, RS, Brazil
19  Departamento de Física, Universidade Federal de Santa Catarina, CP 4796-CDP 88040-900 Florianópolis, SC-Brazil
20  Los Alamos National Laboratory, X-2, MS T-085, Los Alamos, NM 87545, USA
21  Department of Physics and Astronomy, University of Delaware, 223 Sharp Laboratory, Newark, DE 19716, USA

(Received 15 June 2004 / Accepted 27 August 2004 )

Abstract
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  $\ell=1$ modes, with a common period spacing of 23.0 s. This spacing implies that the mass of PG 1707+427 is  $0.57~M_{\odot}$. Preliminary model fits suggest that the mass determined via asteroseismology is consistent with the mass determined from spectroscopy combined with evolutionary tracks.


Key words: stars: evolution -- stars: white dwarfs -- stars: oscillations -- stars: individual: PG 1707+427

SIMBAD Objects



© ESO 2004