Issue |
A&A
Volume 401, Number 2, April II 2003
|
|
---|---|---|
Page(s) | 639 - 654 | |
Section | Stellar structure and evolution | |
DOI | https://doi.org/10.1051/0004-6361:20030105 | |
Published online | 21 March 2003 |
The everchanging pulsating white dwarf GD358*
1
Instituto de Física da UFRGS, Porto Alegre, RS - Brazil e-mail: kepler@if.ufrgs.br
2
Department of Astronomy & McDonald Observatory, University of Texas, Austin, TX 78712, USA
3
Sloan Digital Sky Survey, Apache Pt. Observatory, PO Box 59, Sunspot, NM 88349, USA
4
Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138, USA e-mail: travis@whitedwarf.org
5
Subaru National Astronomical Observatory of Japan e-mail: kaz@subaru.naoj.org
6
Beijing Astronomical Observatory, Academy of Sciences, Beijing 100080, PR China e-mail: jiang@astro.as.utexas.edu
7
University of Victoria, Wellington, New Zealand
8
Institute of Theoretical Physics and Astronomy, Gostauto 12, Vilnius 2600, Lithuania
9
Mt. Suhora Observatory, Cracow Pedagogical University, Ul. Podchorazych 2, 30-084 Cracow, Poland
10
Jagiellonian University, Krakow, Poland e-mail: zola@oa.uj.edu.pl
11
South African Astronomical Observatory
12
Universitat Tübingen, Germany
13
Université Paul Sabatier, Observatoire Midi-Pyrénées, CNRS/UMR5572, 14 av. E. Belin, 31400 Toulouse, France
14
Observatoire de Paris-Meudon, DAEC, 92195 Meudon, France e-mail: chevreton@obspm.fr
15
Institutt for fysikk, 9037 Tromso, Norway
16
Departamento de Física, Universidade Federal de Santa Catarina, CP 476, CEP 88040-900, Florianópolis, Brazil e-mail: kanaan@fsc.ufsc.br
17
Dept. of Physics and Space Sciences & The SARA Observatory, Florida Institute of Technology, Melbourne, FL 32901, USA
18
University of Florida, 202 Nuclear Sciences Center Gainesville, FL 32611-8300, USA
19
Johnson Space Center, 2101 NASA Road 1, Mail Code GT2, Houston, TX 77058, USA
20
University of Minnesota, Department of Physics & Astronomy, 116 Church St. S.E., Minneapolis, MN 55455, USA
21
University of Georgia at Athens, Department of Physics and Astronomy, Athens, GA 30602-2451, USA
22
Middle Tennessee State University, Department of Physics and Astronomy Murfreesboro, TN 37132, USA
23
Department of Physics and Astronomy, Iowa State University, Ames, IA 50011, USA
24
Universidade de Vigo, Depto. de Fisica Aplicada, Facultade de Ciencias, Campus Marcosende-Lagoas, 36200 Vigo (Pontevedra), Spain e-mail: ulla@uvigo.es
25
Los Alamos National Laboratory, X-2, MS T-085 Los Alamos, NM 87545, USA
Corresponding author: S. O. Kepler, kepler@if.ufrgs.br
Received:
6
December
2002
Accepted:
21
January
2003
We report 323 hours of
nearly uninterrupted time series photometric observations of the DBV
star GD 358
acquired with the Whole Earth Telescope (WET) during May 23rd to
June 8th, 2000.
We acquired more than 232 000 independent measurements.
We also report on 48 hours of time-series photometric observations
in Aug 1996.
We detected the non-radial g-modes consistent with degree and
radial order 8 to 20 and their linear combinations up to 6th order.
We also detect, for the first time, a high amplitude
mode, with a period of 796 s.
In the 2000 WET data, the largest amplitude modes are similar to
those detected with the
WET observations of 1990 and 1994, but
the highest combination order previously detected was 4th order.
At one point during the
1996 observations, most of the pulsation energy was transferred into the
radial order
mode, which
displayed a sinusoidal pulse shape
in spite of the large amplitude.
The multiplet structure of the individual modes changes from
year to year, and during the 2000 observations only the
mode
displays clear normal triplet structure.
Even though the pulsation amplitudes change on timescales of days and years,
the eigenfrequencies remain essentially the same,
showing the stellar structure is not changing on
any dynamical timescale.
Key words: stars: white dwarfs / stars: variables: general / stars: oscillations / stars: individual: GD 358 / stars: evolution
© ESO, 2003
Current usage metrics show cumulative count of Article Views (full-text article views including HTML views, PDF and ePub downloads, according to the available data) and Abstracts Views on Vision4Press platform.
Data correspond to usage on the plateform after 2015. The current usage metrics is available 48-96 hours after online publication and is updated daily on week days.
Initial download of the metrics may take a while.