Abstract
One of the most spectacular applications of the calculations presented in the foregoing chapters was the identification of absorption features in the optical spectra of magnetized white dwarf stars, which had defied interpretation for almost 50 years, in terms of stationary components of hydrogen lines in magnetic fields of several 105 T (Angel et al. 1985; Greenstein et al. 1985; Wunner et al. 1985b; Schmidt et al., 1986a,b). By stationary components we mean those transitions whose wavelengths go through maxima or minima as functions of the magnetic field strength. These lines, between 300 nm and 1000 nm, are particularly well recognized if Fig. 4.2a is viewed sideways at flat angles. The fact that these transitions can produce sharp absorption features in white dwarf spectra is obvious when one considers that the magnetic field strength varies (in a dipolar geometry) by a factor of two across the white dwarf and thus all fast moving wavelengths are smeared out.
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References
Achilleos, N., Remillard, R.A., and Wickramasinghe, D.T. (1991): Serendipitous identifications of two magnetic white dwarfs. Mon. Not. R. astr. Soc. 253, 522.
Angel, J.R.P. (1978): Magnetic white dwarfs. Ann. Rev. Astron. Astrophys. 16, 487.
Angel, J.R.P., Liebert, J., and Stockman, H.S. (1985): The optical spectrum of hydrogen at 160–350 million gauss in the white dwarf Grw+70°8247. Astrophys. J. 292, 260.
Bergeron, P., Ruiz, M-T., and Leggett, S.K. (1992): Discovery of two cool magnetic white dwarfs. Astrophys. J. 400, 315.
Bergeron, P., Ruiz, M-T., and Leggett, S.K. (1993): G42–46: an unresolved double degenerate binary containing a magnetic DA component. Astrophys. J. 407, 733.
Chanmugam, G. (1992): Magnetic fields of degenerate stars. Ann. Rev. Astron. Astrophys. 30, 143.
Cohen, M. H., Putney, A., and Goodrich, R. W. (1993): The strong magnetic field in G227–35. Astrophys. J. 405, L67.
Friedrich, S. (1993): Theorie und Beobachtung von Spektren magnetischer Weißer Zwergsterne. PhD thesis, Univ. Tübingen.
Greenstein, J.L., and Matthews, M.S. (1957): Studies of the white dwarfs. I. Broad features in white dwarf spectra. Astrophys. J. 126, 14.
Greenstein, J.L., Henry, R.J.W., and O’Connell, R.F. (1985): Further identifications of hydrogen in Grw+70°8247. Astrophys. J. 289, L25.
Henry, R.J.W., and O’Connell, R.F. (1985): Hydrogen spectrum in magnetic white dwarfs: Hα, Hβ, and Hγ transitions. Publ. Astron. Soc. Pac, 97, 333.
Kemic, S.B. (1974a): Hydrogen and helium features in magnetic white dwarfs. Astrophys. J. 193, 213.
Kemp, J.C., Swedlund, J.B., Landstreet, J.D., and Angel, J.R.P. (1970): Discovery of circularly polarized light from a white dwarf. Astrophys. J. 161, L77.
Koester, D. and Chanmugam, G. (1990): Physics of white dwarf stars. Rep. Prog. Phys. 53, 837.
Landstreet, J.D. (1992): Magnetic fields at the surfaces of stars. Astron. Astrophys. Rev. 4, 35.
Latter, W. B., Schmidt, G. D., and Green, R. F. (1987): The rotationally modulated Zeeman spectrum at nearly 109 Gauss of the white dwarf PG 1031+234. Astrophys. J. 320, 308.
Liebert, J., Bergeron, P., Schmidt, G. D., and Saffer, R. A. (1993): Discovery of a magnetic/nonmagnetic double-degenerate binary system. Astrophys. J. 418, 426.
Liebert, J., Schmidt, G. D., Lesser, M., Stepanian, J. A., Lipovetsky, V. A., Chaffee, F. H., Foltz, C. B., and Bergeron, P. (1994): Discovery of a dwarf carbon star with a white dwarf companion and of a highly magnetic degenerate star. Astrophys. J. 421, 733.
Minkowski, R. (1938): Ann. Rept. Dir. Mt. Wilson Obs. 28.
Östreicher, R., Seifert, W., Friedrich, S., Ruder, H., Schaich, M., Wolf, D. and Wunner, G. (1992): Hydrogen in the strong magnetic field of the white dwarf PG 1031+234. Astron. Astrophys. 257, 353.
Schmidt, G.D., Stockman, H.S., and Grandi, S.A. (1986a): The optical continua of magnetic variables. Astrophys. J. 300, 804.
Schmidt, G.D., West, S.C., Liebert, J., Green, R.F., and Stockman, H.S. (1986b): The new magnetic white dwarf PG 1031+234: polarization and field structure at more than 500 million gauss. Astrophys. J. 309, 218.
Schmidt, G.D., Stockman, H.S., and Smith, P.S. (1992): Discovery of a sub-megagauss magnetic white dwarf through spectropolarimetry. Astrophys. J. Lett. 398, L57.
Schwope, A. D., Beuermann, K., Jordan, S., and Thomas, H.-C., (1993) Cyclotron and Zeeman spectroscopy of MR Serpentis in low and high states of accretion. Astron. Astrophys. 278, 487.
Wickramasinghe, D.T. and Cropper, M. (1988): Spectropolarimetry of the magnetic white dwarf PG1015+014: evidence for a 100-MG field. Mon. Not. R. astr. Soc. 235, 1451.
Wickramasinghe, D.T. and Ferrario, L. (1988): A centered dipole model for the high field magnetic white dwarf Grw+70°8247. Astrophys. J. 327, 222.
Wunner, G., Rösner, W., Herold, H., and Ruder, H. (1985b): Stationary hydrogen lines in white dwarf magnetic fields and the spectrum of the magnetic degenerate Grw+70°8247. Astron. Astrophys. 149, 102.
Zimmerman, M.L., Kash, M.M., and Kleppner, D. (1980): Evidence of an approximate symmetry for hydrogen in a uniform magnetic field. Phys. Rev. Lett. 45, 1092.
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Ruder, H., Wunner, G., Herold, H., Geyer, F. (1994). Stationary Lines and White Dwarf Spectra. In: Atoms in Strong Magnetic Fields. Astronomy and Astrophysics Library. Springer, Berlin, Heidelberg. https://doi.org/10.1007/978-3-642-78820-8_7
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DOI: https://doi.org/10.1007/978-3-642-78820-8_7
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