Observations of the Pulsating White Dwarf G 185–32

A&A 413, 623-634 (2004)
DOI: 10.1051/0004-6361:20031567

Observations of the Pulsating White Dwarf G 185-32

B. G. Castanheira¹, S. O. Kepler¹, P. Moskalik^{2, 3}, S. Zola³, G. Pajdosz³, J. Krzesinski³, D. O'Donoghue⁴, M. Katz⁴, D. Buckley⁴, G. Vauclair⁵, N. Dolez⁵, M. Chevreton⁶, M. A. Barstow⁷, A. Kanaan⁸, O. Giovannini⁹, J. Provencal¹⁰, S. D. Kawaler¹¹, J. C. Clemens¹², R. E. Nather¹³, D. E. Winget¹³, T. K. Watson¹⁴, K. Yanagida¹³, J. S. Dixson¹³, C. J. Hansen¹⁵, P. A. Bradley¹⁶, M. A. Wood¹⁷, D. J. Sullivan¹⁸, S. J. Kleinman¹⁹, E. Meistas²⁰, J.-E. Solheim²¹, A. Bruvold²¹, E. Leibowitz²², T. Mazeh²², D. Koester²³ and M. H. Montgomery²⁴

¹ Instituto de Física, Universidade Federal do Rio Grande do Sul, 91501-900 Porto-Alegre, RS, Brazil
² Copernicus Astronomical Center, Ul. Bartycka 18, 00-716 Warsaw, Poland
³ Mt. Suhora Observatory, Cracow Pedagogical University, Ul. Podchorazych 2, 30-084 Cracow, Poland
⁴ South African Astronomical Observatory, PO Box 9, Observatory 7935, SA
⁵ Université Paul Sabatier, Observatoire Midi-Pyrénées, CNRS/UMR5572, 14 av. E. Belin, 31400 Toulouse, France
⁶ Observatoire de Paris-Meudon, DAEC, 92195 Meudon, France
⁷ Department of Physics and Astronomy, Leicester University, University Road, Leicester, LE1 7RH, UK
⁸ Departamento de Física, Universidade Federal de Santa Catarina, CP 476, 88040-900, Florianópolis, Brazil
⁹ Departamento de Física e Química, Universidade de Caxias do Sul, Caxias do Sul, RS - CEP 95001-970, Brazil
¹⁰ Department of Physics and Astronomy, University of Delaware, Newark, DE 19716, USA
¹¹ Department of Physics and Astronomy, Iowa State University, Ames, IA 50011, USA
¹² Department of Physics, University of North Carolina, Chapel Hill, NC 27599-3255, USA
¹³ Department of Astronomy and McDonald Observatory, University of Texas, Austin, TX 78712, USA
¹⁴ Southwestern University, Georgetown, USA
¹⁵ JILA, University of Colorado, Boulder, CO, USA
¹⁶ Los Alamos National Laboratory, X-2, MS T-085, Los Alamos, NM 87545, USA
¹⁷ Dept. of Physics and Space Sciences & The SARA Observatory, Florida Institute of Technology, Melbourne, FL 32901, USA
¹⁸ Victoria University of Wellington, PO Box 600, Wellington, New Zealand
¹⁹ Sloan Digital Sky Survey, Apache Pt. Observatory, PO Box 59, Sunspot, NM 88349, USA
²⁰ Institute of Theoretical Physics and Astronomy, Gostauto 12, Vilnius 2600, Lithuania
²¹ Institutt for Fysikk, Universitetet i Tromsø, 9037 Tromsø, Norway
²² Wise Observatory, Tel Aviv University, Tel Aviv 69978, Israel
²³ Institut für Theoretische Physik und Astrophysik, Universität Kiel, Germany
²⁴ Institute of Astronomy, Madingley Road, Cambridge, CB3 0HA, UK

(Received 6 June 2003 / Accepted 23 September 2003 )

Abstract
We observed the pulsating hydrogen atmosphere white dwarf G 185-32 with the Whole Earth Telescope in 1992. We report on a weighted Fourier transform of the data detecting 18 periodicities in its light curve. Using the Hubble Space Telescope Faint Object Spectrograph time resolved spectroscopy, and the wavelength dependence of the relative amplitudes, we identify the spherical harmonic degree ( $\ell$ ) for 14 pulsation signals. We also compare the determinations of effective temperature and surface gravity using the excited modes and atmospheric methods, obtaining $T_{{\rm eff}}=11\,960$ $\pm$ 80 K, $\log g=8.02$ $\pm$ 0.04 and M=0.617 $\pm$ $0.024~M_{\odot}$ .

Key words: stars: white dwarfs -- stars: variables: general -- stars: oscillations -- stars: individual: G 185-32 -- stars: evolution

Offprint request: B. G. Castanheira, barbara@if.ufrgs.br

SIMBAD Objects in preparation