The Library

Zeeman tomography of magnetic white dwarfs. II, The quadrupole-dominated magnetic field of HE 1045-0908

Tools

Euchner, F., Reinsch, K. (Klaus), Jordan, S. (Stefan), Beuermann, K. (Klaus) and Gaensicke, B. T. (Boris T.). (2005) Zeeman tomography of magnetic white dwarfs. II, The quadrupole-dominated magnetic field of HE 1045-0908. Astronomy & Astrophysics, Vol.442 (No.2). pp. 651-660. ISSN 0004-6361

[img] PDF
WRAP_Gansicke_93_Zeeman_tomography.pdf - Requires a PDF viewer such as GSview, Xpdf or Adobe Acrobat Reader
Download (1348Kb)

Abstract

We report time-resolved optical flux and circular polarization spectroscopy of the magnetic DA white dwarf HE 1045−0908 obtained with FORS1 at the ESO VLT. Considering published results, we estimate a likely rotational period of P rot 2.7 h, but cannot exclude values as high as about 9 h. Our detailed Zeeman tomographic analysis reveals a field structure which is dominated by a quadrupole and contains additional dipole and octupole contributions, and which does not depend strongly on the assumed value of the period. A good fit to the Zeeman flux and polarization spectra is obtained if all field components are centred and inclinations of their magnetic axes with respect to each other are allowed for. The fit can be slightly improved if an offset from the centre of the star is included. The prevailing surface field strength is 16 MG, but values between 10 and ∼ 75 MG do occur. We derive an effective photospheric temperature of HE 1045−0908 of T eff = 10 000 ± 1000 K. The tomographic code makes use of an extensive database of pre-computed Zeeman spectra (Paper I).

Item Type: Journal Article
Subjects: Q Science > QB Astronomy
Divisions: Faculty of Science > Physics
Library of Congress Subject Headings (LCSH): White dwarf stars, Magnetic stars, Stars -- Atmospheres
Journal or Publication Title: Astronomy & Astrophysics
Publisher: EDP Sciences
ISSN: 0004-6361
Official Date: November 2005
Volume: Vol.442
Number: No.2
Page Range: pp. 651-660
Identification Number: 10.1051/0004-6361:20053038
Status: Peer Reviewed
Access rights to Published version: Open Access
Funder: Germany. Bundesministerium für Bildung und Forschung (BMBF), Deutsche Forschungsanstalt für Luft- und Raumfahrt (DLR), Particle Physics and Astronomy Research Council (Great Britain) (PPARC)
Grant number: 50OR9903 6 (BMBF/DLR)
References:

Aznar Cuadrado, R., Jordan, S., Napiwotzki, R., et al. 2004, A&A,
423, 1081
Braithwaite, J., & Spruit, H. C. 2004, Nature, 431, 819
Burleigh, M. R., Jordan, S., & Schweizer, W. 1999, ApJ, 510, L37
Cumming, A. 2002, MNRAS, 333, 589
Donati, J.-F., Achilleos, N., Matthews, J. M., & Wesemael, F. 1994,
A&A, 285, 285
Euchner, F., Jordan, S., Beuermann, K., Gänsicke, B. T., & Hessman,
F. V. 2002, A&A, 390, 633 (Paper I)
Euchner, F., Jordan, S., Reinsch, K., Beuermann, K., & Gänsicke,
B. T. 2005, in Proc. of the 14th European Workshop on White
Dwarfs, ed. D. Koester, & S. Moehler (San Francisco: ASP), ASP
Conf. Ser., 334, 269
Fabrika, S., & Valyavin, G. 1999, in 11th European Workshop on
White Dwarfs, ed. J.-E. Solheim, & E. G. Meištas (San Francisco:
ASP), ASP Conf. Ser., 169, 225
Forster, H., Strupat, W., Rösner, W., et al. 1984, J. Phys. V, 17, 1301
Gauß, C. F. 1838, in Resultate magn. Verein 1838, reprinted in:Werke,
5, 121
Jehin, E., O’Brien, K., & Szeifert, T. 2004, FORS1+2
User Manual 2.8, European Southern Observatory,
VLT-MAN-ESO-13100-1543
Jordan, S., Werner, K., & O’Toole, S. J. 2005, A&A, 432, 273
Langel, R. A. 1987, in Geomagnetism, ed. J. A. Jacobs, Vol. 1
(London: Academic Press), 249
Liebert, J., Bergeron, P., & Holberg, J. B. 2003, AJ, 125, 348
Maxted, P. F. L., Ferrario, L., Marsh, T. R., & Wickramasinghe, D. T.
2000, MNRAS, 315, L41
Muslimov, A. G., Van Horn, H. M., & Wood, M. A. 1995, ApJ, 442,
758
O’Toole, S. J., Jordan, S., Friedrich, S., & Heber, U. 2005, A&A, 437,
227
Reimers, D., Jordan, S., Köhler, T., & Wisotzki, L. 1994, A&A, 285,
995
Reimers, D., Jordan, S., & Christlieb, N. 2004, A&A, 414, 1105
Rösner,W.,Wunner, G., Herold, H., & Ruder, H. 1984, J. Phys. V, 17,
29
Schmidt, G. D., Vennes, S., Wickramasinghe, D. T., & Ferrario, L.
2001, MNRAS, 328, 203
Schmidt, G. D., Harris, H. C., Liebert, J., et al. 2003, ApJ, 595, 1101
Tout, C. A., Wickramasinghe, D. T., & Ferrario, L. 2004, MNRAS,
355, L13
Wendell, C. E., van Horn, H. M., & Sargent, D. 1987, ApJ, 313, 284
Wickramasinghe, D. T. & Ferrario, L. 2000, PASP, 112, 873
Wisotzki, L., Köhler, T., Groote, D., & Reimers, D. 1996, A&AS, 115,
227
Wunner, G., Rösner, W., Herold, H., & Ruder, H. 1985, A&A, 149,
102
Zhang, E.-H., Robinson, E. L., & Nather, R. E. 1986, ApJ, 305, 740
URI: http://wrap.warwick.ac.uk/id/eprint/3581

Request changes or add full text files to a record

Actions (login required)

View Item View Item

Document Downloads

More statistics for this item...